Add Origin header validation

- Fixes #695
- Does not implement Host header validation yet

Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>
This commit is contained in:
Daniel Garnier-Moiroux 2026-02-04 18:56:23 +01:00 • committed by Daniel Garnier-Moiroux
commit 96c9bbe745
17 changed files with 1804 additions and 30 deletions

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@ -8,7 +8,34 @@ import java.util.Map;
import io.modelcontextprotocol.server.McpServer;
import io.modelcontextprotocol.server.McpServerFeatures;
import io.modelcontextprotocol.server.transport.HttpServletStreamableServerTransportProvider;
import io.modelcontextprotocol.spec.McpSchema.*;
import io.modelcontextprotocol.spec.McpSchema.AudioContent;
import io.modelcontextprotocol.spec.McpSchema.BlobResourceContents;
import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
import io.modelcontextprotocol.spec.McpSchema.CompleteResult;
import io.modelcontextprotocol.spec.McpSchema.CreateMessageRequest;
import io.modelcontextprotocol.spec.McpSchema.CreateMessageResult;
import io.modelcontextprotocol.spec.McpSchema.ElicitRequest;
import io.modelcontextprotocol.spec.McpSchema.ElicitResult;
import io.modelcontextprotocol.spec.McpSchema.EmbeddedResource;
import io.modelcontextprotocol.spec.McpSchema.GetPromptResult;
import io.modelcontextprotocol.spec.McpSchema.ImageContent;
import io.modelcontextprotocol.spec.McpSchema.JsonSchema;
import io.modelcontextprotocol.spec.McpSchema.LoggingLevel;
import io.modelcontextprotocol.spec.McpSchema.LoggingMessageNotification;
import io.modelcontextprotocol.spec.McpSchema.ProgressNotification;
import io.modelcontextprotocol.spec.McpSchema.Prompt;
import io.modelcontextprotocol.spec.McpSchema.PromptArgument;
import io.modelcontextprotocol.spec.McpSchema.PromptMessage;
import io.modelcontextprotocol.spec.McpSchema.PromptReference;
import io.modelcontextprotocol.spec.McpSchema.ReadResourceResult;
import io.modelcontextprotocol.spec.McpSchema.Resource;
import io.modelcontextprotocol.spec.McpSchema.ResourceTemplate;
import io.modelcontextprotocol.spec.McpSchema.Role;
import io.modelcontextprotocol.spec.McpSchema.SamplingMessage;
import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
import io.modelcontextprotocol.spec.McpSchema.TextContent;
import io.modelcontextprotocol.spec.McpSchema.TextResourceContents;
import io.modelcontextprotocol.spec.McpSchema.Tool;
import org.apache.catalina.Context;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.startup.Tomcat;

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@ -0,0 +1,132 @@
/*
* Copyright 2026-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import io.modelcontextprotocol.util.Assert;
/**
* Default implementation of {@link ServerTransportSecurityValidator} that validates the
* Origin header against a list of allowed origins.
*
* <p>
* Supports exact matches and wildcard port patterns (e.g., "http://example.com:*").
*
* @author Daniel Garnier-Moiroux
* @see ServerTransportSecurityValidator
* @see ServerTransportSecurityException
*/
public class DefaultServerTransportSecurityValidator implements ServerTransportSecurityValidator {
private static final String ORIGIN_HEADER = "Origin";
private static final ServerTransportSecurityException INVALID_ORIGIN = new ServerTransportSecurityException(403,
"Invalid Origin header");
private final List<String> allowedOrigins;
/**
* Creates a new validator with the specified allowed origins.
* @param allowedOrigins List of allowed origin patterns. Supports exact matches
* (e.g., "http://example.com:8080") and wildcard ports (e.g., "http://example.com:*")
*/
public DefaultServerTransportSecurityValidator(List<String> allowedOrigins) {
Assert.notNull(allowedOrigins, "allowedOrigins must not be null");
this.allowedOrigins = allowedOrigins;
}
@Override
public void validateHeaders(Map<String, List<String>> headers) throws ServerTransportSecurityException {
for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
if (ORIGIN_HEADER.equalsIgnoreCase(entry.getKey())) {
List<String> values = entry.getValue();
if (values != null && !values.isEmpty()) {
validateOrigin(values.get(0));
}
break;
}
}
}
/**
* Validates a single origin value against the allowed origins. Subclasses can
* override this method to customize origin validation logic.
* @param origin The origin header value, or null if not present
* @throws ServerTransportSecurityException if the origin is not allowed
*/
protected void validateOrigin(String origin) throws ServerTransportSecurityException {
// Origin absent = no validation needed (same-origin request)
if (origin == null || origin.isBlank()) {
return;
}
for (String allowed : allowedOrigins) {
if (allowed.equals(origin)) {
return;
}
else if (allowed.endsWith(":*")) {
// Wildcard port pattern: "http://example.com:*"
String baseOrigin = allowed.substring(0, allowed.length() - 2);
if (origin.equals(baseOrigin) || origin.startsWith(baseOrigin + ":")) {
return;
}
}
}
throw INVALID_ORIGIN;
}
/**
* Creates a new builder for constructing a DefaultServerTransportSecurityValidator.
* @return A new builder instance
*/
public static Builder builder() {
return new Builder();
}
/**
* Builder for creating instances of {@link DefaultServerTransportSecurityValidator}.
*/
public static class Builder {
private final List<String> allowedOrigins = new ArrayList<>();
/**
* Adds an allowed origin pattern.
* @param origin The origin to allow (e.g., "http://localhost:8080" or
* "http://example.com:*")
* @return this builder instance
*/
public Builder allowedOrigin(String origin) {
this.allowedOrigins.add(origin);
return this;
}
/**
* Adds multiple allowed origin patterns.
* @param origins The origins to allow
* @return this builder instance
*/
public Builder allowedOrigins(List<String> origins) {
Assert.notNull(origins, "origins must not be null");
this.allowedOrigins.addAll(origins);
return this;
}
/**
* Builds the validator instance.
* @return A new DefaultServerTransportSecurityValidator
*/
public DefaultServerTransportSecurityValidator build() {
return new DefaultServerTransportSecurityValidator(allowedOrigins);
}
}
}

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@ -1,5 +1,5 @@
/*
* Copyright 2024 - 2024 the original author or authors.
* Copyright 2024 - 2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
@ -8,6 +8,9 @@ import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.time.Duration;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;
@ -142,6 +145,11 @@ public class HttpServletSseServerTransportProvider extends HttpServlet implement
*/
private KeepAliveScheduler keepAliveScheduler;
/**
* Security validator for validating HTTP requests.
*/
private final ServerTransportSecurityValidator securityValidator;
/**
* Creates a new HttpServletSseServerTransportProvider instance with a custom SSE
* endpoint.
@ -153,23 +161,25 @@ public class HttpServletSseServerTransportProvider extends HttpServlet implement
* @param keepAliveInterval The interval for keep-alive pings, or null to disable
* keep-alive functionality
* @param contextExtractor The extractor for transport context from the request.
* @deprecated Use the builder {@link #builder()} instead for better configuration
* options.
* @param securityValidator The security validator for validating HTTP requests.
*/
private HttpServletSseServerTransportProvider(McpJsonMapper jsonMapper, String baseUrl, String messageEndpoint,
String sseEndpoint, Duration keepAliveInterval,
McpTransportContextExtractor<HttpServletRequest> contextExtractor) {
McpTransportContextExtractor<HttpServletRequest> contextExtractor,
ServerTransportSecurityValidator securityValidator) {
Assert.notNull(jsonMapper, "JsonMapper must not be null");
Assert.notNull(messageEndpoint, "messageEndpoint must not be null");
Assert.notNull(sseEndpoint, "sseEndpoint must not be null");
Assert.notNull(contextExtractor, "Context extractor must not be null");
Assert.notNull(securityValidator, "Security validator must not be null");
this.jsonMapper = jsonMapper;
this.baseUrl = baseUrl;
this.messageEndpoint = messageEndpoint;
this.sseEndpoint = sseEndpoint;
this.contextExtractor = contextExtractor;
this.securityValidator = securityValidator;
if (keepAliveInterval != null) {
@ -246,6 +256,15 @@ public class HttpServletSseServerTransportProvider extends HttpServlet implement
return;
}
try {
Map<String, List<String>> headers = extractHeaders(request);
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
response.sendError(e.getStatusCode(), e.getMessage());
return;
}
response.setContentType("text/event-stream");
response.setCharacterEncoding(UTF_8);
response.setHeader("Cache-Control", "no-cache");
@ -311,6 +330,15 @@ public class HttpServletSseServerTransportProvider extends HttpServlet implement
return;
}
try {
Map<String, List<String>> headers = extractHeaders(request);
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
response.sendError(e.getStatusCode(), e.getMessage());
return;
}
// Get the session ID from the request parameter
String sessionId = request.getParameter("sessionId");
if (sessionId == null) {
@ -411,6 +439,21 @@ public class HttpServletSseServerTransportProvider extends HttpServlet implement
}
}
/**
* Extracts all headers from the HTTP servlet request into a map.
* @param request The HTTP servlet request
* @return A map of header names to their values
*/
private Map<String, List<String>> extractHeaders(HttpServletRequest request) {
Map<String, List<String>> headers = new HashMap<>();
Enumeration<String> names = request.getHeaderNames();
while (names.hasMoreElements()) {
String name = names.nextElement();
headers.put(name, Collections.list(request.getHeaders(name)));
}
return headers;
}
/**
* Cleans up resources when the servlet is being destroyed.
* <p>
@ -547,6 +590,8 @@ public class HttpServletSseServerTransportProvider extends HttpServlet implement
private Duration keepAliveInterval;
private ServerTransportSecurityValidator securityValidator = ServerTransportSecurityValidator.NOOP;
/**
* Sets the JsonMapper implementation to use for serialization/deserialization. If
* not specified, a JacksonJsonMapper will be created from the configured
@ -621,6 +666,18 @@ public class HttpServletSseServerTransportProvider extends HttpServlet implement
return this;
}
/**
* Sets the security validator for validating HTTP requests.
* @param securityValidator The security validator to use. Must not be null.
* @return This builder instance
* @throws IllegalArgumentException if securityValidator is null
*/
public Builder securityValidator(ServerTransportSecurityValidator securityValidator) {
Assert.notNull(securityValidator, "Security validator must not be null");
this.securityValidator = securityValidator;
return this;
}
/**
* Builds a new instance of HttpServletSseServerTransportProvider with the
* configured settings.
@ -633,7 +690,7 @@ public class HttpServletSseServerTransportProvider extends HttpServlet implement
}
return new HttpServletSseServerTransportProvider(
jsonMapper == null ? McpJsonMapper.getDefault() : jsonMapper, baseUrl, messageEndpoint, sseEndpoint,
keepAliveInterval, contextExtractor);
keepAliveInterval, contextExtractor, securityValidator);
}
}

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@ -1,5 +1,5 @@
/*
* Copyright 2024-2024 the original author or authors.
* Copyright 2024-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
@ -7,6 +7,11 @@ package io.modelcontextprotocol.server.transport;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@ -58,15 +63,23 @@ public class HttpServletStatelessServerTransport extends HttpServlet implements
private volatile boolean isClosing = false;
/**
* Security validator for validating HTTP requests.
*/
private final ServerTransportSecurityValidator securityValidator;
private HttpServletStatelessServerTransport(McpJsonMapper jsonMapper, String mcpEndpoint,
McpTransportContextExtractor<HttpServletRequest> contextExtractor) {
McpTransportContextExtractor<HttpServletRequest> contextExtractor,
ServerTransportSecurityValidator securityValidator) {
Assert.notNull(jsonMapper, "jsonMapper must not be null");
Assert.notNull(mcpEndpoint, "mcpEndpoint must not be null");
Assert.notNull(contextExtractor, "contextExtractor must not be null");
Assert.notNull(securityValidator, "Security validator must not be null");
this.jsonMapper = jsonMapper;
this.mcpEndpoint = mcpEndpoint;
this.contextExtractor = contextExtractor;
this.securityValidator = securityValidator;
}
@Override
@ -122,6 +135,15 @@ public class HttpServletStatelessServerTransport extends HttpServlet implements
return;
}
try {
Map<String, List<String>> headers = extractHeaders(request);
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
response.sendError(e.getStatusCode(), e.getMessage());
return;
}
McpTransportContext transportContext = this.contextExtractor.extract(request);
String accept = request.getHeader(ACCEPT);
@ -209,6 +231,21 @@ public class HttpServletStatelessServerTransport extends HttpServlet implements
writer.flush();
}
/**
* Extracts all headers from the HTTP servlet request into a map.
* @param request The HTTP servlet request
* @return A map of header names to their values
*/
private Map<String, List<String>> extractHeaders(HttpServletRequest request) {
Map<String, List<String>> headers = new HashMap<>();
Enumeration<String> names = request.getHeaderNames();
while (names.hasMoreElements()) {
String name = names.nextElement();
headers.put(name, Collections.list(request.getHeaders(name)));
}
return headers;
}
/**
* Cleans up resources when the servlet is being destroyed.
* <p>
@ -243,6 +280,8 @@ public class HttpServletStatelessServerTransport extends HttpServlet implements
private McpTransportContextExtractor<HttpServletRequest> contextExtractor = (
serverRequest) -> McpTransportContext.EMPTY;
private ServerTransportSecurityValidator securityValidator = ServerTransportSecurityValidator.NOOP;
private Builder() {
// used by a static method
}
@ -288,6 +327,18 @@ public class HttpServletStatelessServerTransport extends HttpServlet implements
return this;
}
/**
* Sets the security validator for validating HTTP requests.
* @param securityValidator The security validator to use. Must not be null.
* @return this builder instance
* @throws IllegalArgumentException if securityValidator is null
*/
public Builder securityValidator(ServerTransportSecurityValidator securityValidator) {
Assert.notNull(securityValidator, "Security validator must not be null");
this.securityValidator = securityValidator;
return this;
}
/**
* Builds a new instance of {@link HttpServletStatelessServerTransport} with the
* configured settings.
@ -297,7 +348,7 @@ public class HttpServletStatelessServerTransport extends HttpServlet implements
public HttpServletStatelessServerTransport build() {
Assert.notNull(mcpEndpoint, "Message endpoint must be set");
return new HttpServletStatelessServerTransport(jsonMapper == null ? McpJsonMapper.getDefault() : jsonMapper,
mcpEndpoint, contextExtractor);
mcpEndpoint, contextExtractor, securityValidator);
}
}

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@ -1,5 +1,5 @@
/*
* Copyright 2024-2024 the original author or authors.
* Copyright 2024-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
@ -9,7 +9,11 @@ import java.io.IOException;
import java.io.PrintWriter;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.locks.ReentrantLock;
@ -119,6 +123,11 @@ public class HttpServletStreamableServerTransportProvider extends HttpServlet
*/
private KeepAliveScheduler keepAliveScheduler;
/**
* Security validator for validating HTTP requests.
*/
private final ServerTransportSecurityValidator securityValidator;
/**
* Constructs a new HttpServletStreamableServerTransportProvider instance.
* @param jsonMapper The JsonMapper to use for JSON serialization/deserialization of
@ -127,19 +136,24 @@ public class HttpServletStreamableServerTransportProvider extends HttpServlet
* messages via HTTP. This endpoint will handle GET, POST, and DELETE requests.
* @param disallowDelete Whether to disallow DELETE requests on the endpoint.
* @param contextExtractor The extractor for transport context from the request.
* @param keepAliveInterval The interval for keep-alive pings. If null, no keep-alive
* will be scheduled.
* @param securityValidator The security validator for validating HTTP requests.
* @throws IllegalArgumentException if any parameter is null
*/
private HttpServletStreamableServerTransportProvider(McpJsonMapper jsonMapper, String mcpEndpoint,
boolean disallowDelete, McpTransportContextExtractor<HttpServletRequest> contextExtractor,
Duration keepAliveInterval) {
Duration keepAliveInterval, ServerTransportSecurityValidator securityValidator) {
Assert.notNull(jsonMapper, "JsonMapper must not be null");
Assert.notNull(mcpEndpoint, "MCP endpoint must not be null");
Assert.notNull(contextExtractor, "Context extractor must not be null");
Assert.notNull(securityValidator, "Security validator must not be null");
this.jsonMapper = jsonMapper;
this.mcpEndpoint = mcpEndpoint;
this.disallowDelete = disallowDelete;
this.contextExtractor = contextExtractor;
this.securityValidator = securityValidator;
if (keepAliveInterval != null) {
@ -246,6 +260,15 @@ public class HttpServletStreamableServerTransportProvider extends HttpServlet
return;
}
try {
Map<String, List<String>> headers = extractHeaders(request);
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
response.sendError(e.getStatusCode(), e.getMessage());
return;
}
List<String> badRequestErrors = new ArrayList<>();
String accept = request.getHeader(ACCEPT);
@ -373,6 +396,15 @@ public class HttpServletStreamableServerTransportProvider extends HttpServlet
return;
}
try {
Map<String, List<String>> headers = extractHeaders(request);
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
response.sendError(e.getStatusCode(), e.getMessage());
return;
}
List<String> badRequestErrors = new ArrayList<>();
String accept = request.getHeader(ACCEPT);
@ -536,6 +568,15 @@ public class HttpServletStreamableServerTransportProvider extends HttpServlet
return;
}
try {
Map<String, List<String>> headers = extractHeaders(request);
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
response.sendError(e.getStatusCode(), e.getMessage());
return;
}
if (this.disallowDelete) {
response.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED);
return;
@ -586,6 +627,21 @@ public class HttpServletStreamableServerTransportProvider extends HttpServlet
return;
}
/**
* Extracts all headers from the HTTP servlet request into a map.
* @param request The HTTP servlet request
* @return A map of header names to their values
*/
private Map<String, List<String>> extractHeaders(HttpServletRequest request) {
Map<String, List<String>> headers = new HashMap<>();
Enumeration<String> names = request.getHeaderNames();
while (names.hasMoreElements()) {
String name = names.nextElement();
headers.put(name, Collections.list(request.getHeaders(name)));
}
return headers;
}
/**
* Sends an SSE event to a client with a specific ID.
* @param writer The writer to send the event through
@ -774,6 +830,8 @@ public class HttpServletStreamableServerTransportProvider extends HttpServlet
private Duration keepAliveInterval;
private ServerTransportSecurityValidator securityValidator = ServerTransportSecurityValidator.NOOP;
/**
* Sets the JsonMapper to use for JSON serialization/deserialization of MCP
* messages.
@ -833,6 +891,18 @@ public class HttpServletStreamableServerTransportProvider extends HttpServlet
return this;
}
/**
* Sets the security validator for validating HTTP requests.
* @param securityValidator The security validator to use. Must not be null.
* @return this builder instance
* @throws IllegalArgumentException if securityValidator is null
*/
public Builder securityValidator(ServerTransportSecurityValidator securityValidator) {
Assert.notNull(securityValidator, "Security validator must not be null");
this.securityValidator = securityValidator;
return this;
}
/**
* Builds a new instance of {@link HttpServletStreamableServerTransportProvider}
* with the configured settings.
@ -843,7 +913,7 @@ public class HttpServletStreamableServerTransportProvider extends HttpServlet
Assert.notNull(this.mcpEndpoint, "MCP endpoint must be set");
return new HttpServletStreamableServerTransportProvider(
jsonMapper == null ? McpJsonMapper.getDefault() : jsonMapper, mcpEndpoint, disallowDelete,
contextExtractor, keepAliveInterval);
contextExtractor, keepAliveInterval, securityValidator);
}
}

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@ -0,0 +1,48 @@
/*
* Copyright 2026-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
/**
* Exception thrown when security validation fails for an HTTP request. Contains HTTP
* status code and message.
*
* @author Daniel Garnier-Moiroux
* @see ServerTransportSecurityValidator
*/
public class ServerTransportSecurityException extends Exception {
private final int statusCode;
/**
* Creates a new ServerTransportSecurityException with the specified HTTP status code
* and message.
*/
public ServerTransportSecurityException(int statusCode, String message) {
super(message);
this.statusCode = statusCode;
}
public int getStatusCode() {
return statusCode;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null || getClass() != obj.getClass()) {
return false;
}
ServerTransportSecurityException that = (ServerTransportSecurityException) obj;
return statusCode == that.statusCode && java.util.Objects.equals(getMessage(), that.getMessage());
}
@Override
public int hashCode() {
return java.util.Objects.hash(statusCode, getMessage());
}
}

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@ -0,0 +1,36 @@
/*
* Copyright 2026-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
import java.util.List;
import java.util.Map;
/**
* Interface for validating HTTP requests in server transports. Implementations can
* validate Origin headers, Host headers, or any other security-related headers according
* to the MCP specification.
*
* @author Daniel Garnier-Moiroux
* @see DefaultServerTransportSecurityValidator
* @see ServerTransportSecurityException
*/
@FunctionalInterface
public interface ServerTransportSecurityValidator {
/**
* A no-op validator that accepts all requests without validation.
*/
ServerTransportSecurityValidator NOOP = headers -> {
};
/**
* Validates the HTTP headers from an incoming request.
* @param headers A map of header names to their values (multi-valued headers
* supported)
* @throws ServerTransportSecurityException if validation fails
*/
void validateHeaders(Map<String, List<String>> headers) throws ServerTransportSecurityException;
}

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@ -0,0 +1,197 @@
/*
* Copyright 2026-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;
import static org.assertj.core.api.Assertions.assertThatCode;
import static org.assertj.core.api.Assertions.assertThatThrownBy;
/**
* @author Daniel Garnier-Moiroux
*/
class DefaultServerTransportSecurityValidatorTests {
private static final ServerTransportSecurityException INVALID_ORIGIN = new ServerTransportSecurityException(403,
"Invalid Origin header");
private final DefaultServerTransportSecurityValidator validator = DefaultServerTransportSecurityValidator.builder()
.allowedOrigin("http://localhost:8080")
.build();
@Test
void builder() {
assertThatCode(() -> DefaultServerTransportSecurityValidator.builder().build()).doesNotThrowAnyException();
assertThatThrownBy(() -> DefaultServerTransportSecurityValidator.builder().allowedOrigins(null).build())
.isInstanceOf(IllegalArgumentException.class);
}
@Test
void originHeaderMissing() {
assertThatCode(() -> validator.validateHeaders(new HashMap<>())).doesNotThrowAnyException();
}
@Test
void originHeaderListEmpty() {
assertThatCode(() -> validator.validateHeaders(Map.of("Origin", List.of()))).doesNotThrowAnyException();
}
@Test
void caseInsensitive() {
var headers = Map.of("origin", List.of("http://localhost:8080"));
assertThatCode(() -> validator.validateHeaders(headers)).doesNotThrowAnyException();
}
@Test
void exactMatch() {
var headers = originHeader("http://localhost:8080");
assertThatCode(() -> validator.validateHeaders(headers)).doesNotThrowAnyException();
}
@Test
void differentPort() {
var headers = originHeader("http://localhost:3000");
assertThatThrownBy(() -> validator.validateHeaders(headers)).isEqualTo(INVALID_ORIGIN);
}
@Test
void differentHost() {
var headers = originHeader("http://example.com:8080");
assertThatThrownBy(() -> validator.validateHeaders(headers)).isEqualTo(INVALID_ORIGIN);
}
@Test
void differentScheme() {
var headers = originHeader("https://localhost:8080");
assertThatThrownBy(() -> validator.validateHeaders(headers)).isEqualTo(INVALID_ORIGIN);
}
@Nested
class WildcardPort {
private final DefaultServerTransportSecurityValidator wildcardValidator = DefaultServerTransportSecurityValidator
.builder()
.allowedOrigin("http://localhost:*")
.build();
@Test
void anyPortWithWildcard() {
var headers = originHeader("http://localhost:3000");
assertThatCode(() -> wildcardValidator.validateHeaders(headers)).doesNotThrowAnyException();
}
@Test
void noPortWithWildcard() {
var headers = originHeader("http://localhost");
assertThatCode(() -> wildcardValidator.validateHeaders(headers)).doesNotThrowAnyException();
}
@Test
void differentPortWithWildcard() {
var headers = originHeader("http://localhost:8080");
assertThatCode(() -> wildcardValidator.validateHeaders(headers)).doesNotThrowAnyException();
}
@Test
void differentHostWithWildcard() {
var headers = originHeader("http://example.com:3000");
assertThatThrownBy(() -> wildcardValidator.validateHeaders(headers)).isEqualTo(INVALID_ORIGIN);
}
@Test
void differentSchemeWithWildcard() {
var headers = originHeader("https://localhost:3000");
assertThatThrownBy(() -> wildcardValidator.validateHeaders(headers)).isEqualTo(INVALID_ORIGIN);
}
}
@Nested
class MultipleOrigins {
DefaultServerTransportSecurityValidator multipleOriginsValidator = DefaultServerTransportSecurityValidator
.builder()
.allowedOrigin("http://localhost:8080")
.allowedOrigin("http://example.com:3000")
.allowedOrigin("http://myapp.com:*")
.build();
@Test
void matchingOneOfMultiple() {
var headers = originHeader("http://example.com:3000");
assertThatCode(() -> multipleOriginsValidator.validateHeaders(headers)).doesNotThrowAnyException();
}
@Test
void matchingWildcardInMultiple() {
var headers = originHeader("http://myapp.com:9999");
assertThatCode(() -> multipleOriginsValidator.validateHeaders(headers)).doesNotThrowAnyException();
}
@Test
void notMatchingAny() {
var headers = originHeader("http://malicious.example.com:1234");
assertThatThrownBy(() -> multipleOriginsValidator.validateHeaders(headers)).isEqualTo(INVALID_ORIGIN);
}
}
@Nested
class BuilderTests {
@Test
void shouldAddMultipleOriginsWithAllowedOriginsMethod() {
DefaultServerTransportSecurityValidator validator = DefaultServerTransportSecurityValidator.builder()
.allowedOrigins(List.of("http://localhost:8080", "http://example.com:*"))
.build();
var headers = originHeader("http://example.com:3000");
assertThatCode(() -> validator.validateHeaders(headers)).doesNotThrowAnyException();
}
@Test
void shouldCombineAllowedOriginMethods() {
DefaultServerTransportSecurityValidator validator = DefaultServerTransportSecurityValidator.builder()
.allowedOrigin("http://localhost:8080")
.allowedOrigins(List.of("http://example.com:*", "http://test.com:3000"))
.build();
assertThatCode(() -> validator.validateHeaders(originHeader("http://localhost:8080")))
.doesNotThrowAnyException();
assertThatCode(() -> validator.validateHeaders(originHeader("http://example.com:9999")))
.doesNotThrowAnyException();
assertThatCode(() -> validator.validateHeaders(originHeader("http://test.com:3000")))
.doesNotThrowAnyException();
}
}
private static Map<String, List<String>> originHeader(String origin) {
return Map.of("Origin", List.of(origin));
}
}

View file

@ -0,0 +1,292 @@
/*
* Copyright 2026-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
import java.net.URI;
import java.net.http.HttpRequest;
import java.time.Duration;
import java.util.stream.Stream;
import io.modelcontextprotocol.client.McpClient;
import io.modelcontextprotocol.client.McpSyncClient;
import io.modelcontextprotocol.client.transport.HttpClientSseClientTransport;
import io.modelcontextprotocol.client.transport.HttpClientStreamableHttpTransport;
import io.modelcontextprotocol.client.transport.customizer.McpSyncHttpClientRequestCustomizer;
import io.modelcontextprotocol.common.McpTransportContext;
import io.modelcontextprotocol.json.McpJsonMapper;
import io.modelcontextprotocol.server.McpServer;
import io.modelcontextprotocol.spec.McpSchema;
import jakarta.servlet.http.HttpServlet;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleState;
import org.apache.catalina.startup.Tomcat;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.BeforeParameterizedClassInvocation;
import org.junit.jupiter.params.Parameter;
import org.junit.jupiter.params.ParameterizedClass;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;
import static org.junit.jupiter.api.Named.named;
import static org.junit.jupiter.params.provider.Arguments.arguments;
/**
* Test the header security validation for all transport types.
*
* @author Daniel Garnier-Moiroux
*/
@ParameterizedClass
@MethodSource("transports")
class ServerTransportSecurityIntegrationTests {
private static final String DISALLOWED_ORIGIN = "https://malicious.example.com";
@Parameter
private static Transport transport;
private static Tomcat tomcat;
private static String baseUrl;
@BeforeParameterizedClassInvocation
static void createTransportAndStartTomcat(Transport transport) {
var port = TomcatTestUtil.findAvailablePort();
baseUrl = "http://localhost:" + port;
startTomcat(transport.servlet(), port);
}
@AfterAll
static void afterAll() {
stopTomcat();
}
private McpSyncClient mcpClient;
private final TestRequestCustomizer requestCustomizer = new TestRequestCustomizer();
@BeforeEach
void setUp() {
mcpClient = transport.createMcpClient(baseUrl, requestCustomizer);
}
@AfterEach
void tearDown() {
mcpClient.close();
}
@Test
void originAllowed() {
requestCustomizer.setOriginHeader(baseUrl);
var result = mcpClient.initialize();
var tools = mcpClient.listTools();
assertThat(result.protocolVersion()).isNotEmpty();
assertThat(tools.tools()).isEmpty();
}
@Test
void noOrigin() {
requestCustomizer.setOriginHeader(null);
var result = mcpClient.initialize();
var tools = mcpClient.listTools();
assertThat(result.protocolVersion()).isNotEmpty();
assertThat(tools.tools()).isEmpty();
}
@Test
void connectOriginNotAllowed() {
requestCustomizer.setOriginHeader(DISALLOWED_ORIGIN);
assertThatThrownBy(() -> mcpClient.initialize());
}
@Test
void messageOriginNotAllowed() {
requestCustomizer.setOriginHeader(baseUrl);
mcpClient.initialize();
requestCustomizer.setOriginHeader(DISALLOWED_ORIGIN);
assertThatThrownBy(() -> mcpClient.listTools());
}
// ----------------------------------------------------
// Tomcat management
// ----------------------------------------------------
private static void startTomcat(jakarta.servlet.Servlet servlet, int port) {
tomcat = TomcatTestUtil.createTomcatServer("", port, servlet);
try {
tomcat.start();
assertThat(tomcat.getServer().getState()).isEqualTo(LifecycleState.STARTED);
}
catch (Exception e) {
throw new RuntimeException("Failed to start Tomcat", e);
}
}
private static void stopTomcat() {
if (tomcat != null) {
try {
tomcat.stop();
tomcat.destroy();
}
catch (LifecycleException e) {
throw new RuntimeException("Failed to stop Tomcat", e);
}
}
}
// ----------------------------------------------------
// Transport servers to test
// ----------------------------------------------------
/**
* All transport types we want to test. We use a {@link MethodSource} rather than a
* {@link org.junit.jupiter.params.provider.ValueSource} to provide a readable name.
*/
static Stream<Arguments> transports() {
//@formatter:off
return Stream.of(
arguments(named("SSE", new Sse())),
arguments(named("Streamable HTTP", new StreamableHttp())),
arguments(named("Stateless", new Stateless()))
);
//@formatter:on
}
/**
* Represents a server transport we want to test, and how to create a client for the
* resulting MCP Server.
*/
interface Transport {
McpSyncClient createMcpClient(String baseUrl, TestRequestCustomizer requestCustomizer);
HttpServlet servlet();
}
/**
* SSE-based transport.
*/
static class Sse implements Transport {
private final HttpServletSseServerTransportProvider transport;
public Sse() {
transport = HttpServletSseServerTransportProvider.builder()
.messageEndpoint("/mcp/message")
.securityValidator(
DefaultServerTransportSecurityValidator.builder().allowedOrigin("http://localhost:*").build())
.build();
McpServer.sync(transport)
.serverInfo("test-server", "1.0.0")
.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
.build();
}
@Override
public McpSyncClient createMcpClient(String baseUrl, TestRequestCustomizer requestCustomizer) {
var transport = HttpClientSseClientTransport.builder(baseUrl)
.httpRequestCustomizer(requestCustomizer)
.jsonMapper(McpJsonMapper.getDefault())
.build();
return McpClient.sync(transport).initializationTimeout(Duration.ofMillis(500)).build();
}
@Override
public HttpServlet servlet() {
return transport;
}
}
static class StreamableHttp implements Transport {
private final HttpServletStreamableServerTransportProvider transport;
public StreamableHttp() {
transport = HttpServletStreamableServerTransportProvider.builder()
.securityValidator(
DefaultServerTransportSecurityValidator.builder().allowedOrigin("http://localhost:*").build())
.build();
McpServer.sync(transport)
.serverInfo("test-server", "1.0.0")
.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
.build();
}
@Override
public McpSyncClient createMcpClient(String baseUrl, TestRequestCustomizer requestCustomizer) {
var transport = HttpClientStreamableHttpTransport.builder(baseUrl)
.httpRequestCustomizer(requestCustomizer)
.jsonMapper(McpJsonMapper.getDefault())
.openConnectionOnStartup(true)
.build();
return McpClient.sync(transport).initializationTimeout(Duration.ofMillis(500)).build();
}
@Override
public HttpServlet servlet() {
return transport;
}
}
static class Stateless implements Transport {
private final HttpServletStatelessServerTransport transport;
public Stateless() {
transport = HttpServletStatelessServerTransport.builder()
.securityValidator(
DefaultServerTransportSecurityValidator.builder().allowedOrigin("http://localhost:*").build())
.build();
McpServer.sync(transport)
.serverInfo("test-server", "1.0.0")
.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
.build();
}
@Override
public McpSyncClient createMcpClient(String baseUrl, TestRequestCustomizer requestCustomizer) {
var transport = HttpClientStreamableHttpTransport.builder(baseUrl)
.httpRequestCustomizer(requestCustomizer)
.jsonMapper(McpJsonMapper.getDefault())
.openConnectionOnStartup(true)
.build();
return McpClient.sync(transport).initializationTimeout(Duration.ofMillis(500)).build();
}
@Override
public HttpServlet servlet() {
return transport;
}
}
static class TestRequestCustomizer implements McpSyncHttpClientRequestCustomizer {
private String originHeader = null;
@Override
public void customize(HttpRequest.Builder builder, String method, URI endpoint, String body,
McpTransportContext context) {
if (originHeader != null) {
builder.header("Origin", originHeader);
}
}
public void setOriginHeader(String originHeader) {
this.originHeader = originHeader;
}
}
}

View file

@ -1,5 +1,5 @@
/*
* Copyright 2025-2025 the original author or authors.
* Copyright 2025-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
@ -7,6 +7,7 @@ package io.modelcontextprotocol.server.transport;
import java.io.IOException;
import java.time.Duration;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import io.modelcontextprotocol.common.McpTransportContext;
@ -132,6 +133,11 @@ public class WebFluxSseServerTransportProvider implements McpServerTransportProv
*/
private KeepAliveScheduler keepAliveScheduler;
/**
* Security validator for validating HTTP requests.
*/
private final ServerTransportSecurityValidator securityValidator;
/**
* Constructs a new WebFlux SSE server transport provider instance.
* @param jsonMapper The ObjectMapper to use for JSON serialization/deserialization of
@ -144,22 +150,26 @@ public class WebFluxSseServerTransportProvider implements McpServerTransportProv
* @param keepAliveInterval The interval for sending keep-alive pings to clients.
* @param contextExtractor The context extractor to use for extracting MCP transport
* context from HTTP requests. Must not be null.
* @param securityValidator The security validator for validating HTTP requests.
* @throws IllegalArgumentException if either parameter is null
*/
private WebFluxSseServerTransportProvider(McpJsonMapper jsonMapper, String baseUrl, String messageEndpoint,
String sseEndpoint, Duration keepAliveInterval,
McpTransportContextExtractor<ServerRequest> contextExtractor) {
McpTransportContextExtractor<ServerRequest> contextExtractor,
ServerTransportSecurityValidator securityValidator) {
Assert.notNull(jsonMapper, "ObjectMapper must not be null");
Assert.notNull(baseUrl, "Message base path must not be null");
Assert.notNull(messageEndpoint, "Message endpoint must not be null");
Assert.notNull(sseEndpoint, "SSE endpoint must not be null");
Assert.notNull(contextExtractor, "Context extractor must not be null");
Assert.notNull(securityValidator, "Security validator must not be null");
this.jsonMapper = jsonMapper;
this.baseUrl = baseUrl;
this.messageEndpoint = messageEndpoint;
this.sseEndpoint = sseEndpoint;
this.contextExtractor = contextExtractor;
this.securityValidator = securityValidator;
this.routerFunction = RouterFunctions.route()
.GET(this.sseEndpoint, this::handleSseConnection)
.POST(this.messageEndpoint, this::handleMessage)
@ -273,6 +283,14 @@ public class WebFluxSseServerTransportProvider implements McpServerTransportProv
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).bodyValue("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).bodyValue(e.getMessage());
}
McpTransportContext transportContext = this.contextExtractor.extract(request);
return ServerResponse.ok()
@ -332,6 +350,14 @@ public class WebFluxSseServerTransportProvider implements McpServerTransportProv
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).bodyValue("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).bodyValue(e.getMessage());
}
if (request.queryParam("sessionId").isEmpty()) {
return ServerResponse.badRequest().bodyValue(new McpError("Session ID missing in message endpoint"));
}
@ -436,6 +462,8 @@ public class WebFluxSseServerTransportProvider implements McpServerTransportProv
private McpTransportContextExtractor<ServerRequest> contextExtractor = (
serverRequest) -> McpTransportContext.EMPTY;
private ServerTransportSecurityValidator securityValidator = ServerTransportSecurityValidator.NOOP;
/**
* Sets the McpJsonMapper to use for JSON serialization/deserialization of MCP
* messages.
@ -513,6 +541,18 @@ public class WebFluxSseServerTransportProvider implements McpServerTransportProv
return this;
}
/**
* Sets the security validator for validating HTTP requests.
* @param securityValidator The security validator to use. Must not be null.
* @return this builder instance
* @throws IllegalArgumentException if securityValidator is null
*/
public Builder securityValidator(ServerTransportSecurityValidator securityValidator) {
Assert.notNull(securityValidator, "Security validator must not be null");
this.securityValidator = securityValidator;
return this;
}
/**
* Builds a new instance of {@link WebFluxSseServerTransportProvider} with the
* configured settings.
@ -522,7 +562,7 @@ public class WebFluxSseServerTransportProvider implements McpServerTransportProv
public WebFluxSseServerTransportProvider build() {
Assert.notNull(messageEndpoint, "Message endpoint must be set");
return new WebFluxSseServerTransportProvider(jsonMapper == null ? McpJsonMapper.getDefault() : jsonMapper,
baseUrl, messageEndpoint, sseEndpoint, keepAliveInterval, contextExtractor);
baseUrl, messageEndpoint, sseEndpoint, keepAliveInterval, contextExtractor, securityValidator);
}
}

View file

@ -1,5 +1,5 @@
/*
* Copyright 2025-2025 the original author or authors.
* Copyright 2025-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
@ -24,6 +24,7 @@ import reactor.core.publisher.Mono;
import java.io.IOException;
import java.util.List;
import java.util.Map;
/**
* Implementation of a WebFlux based {@link McpStatelessServerTransport}.
@ -46,15 +47,23 @@ public class WebFluxStatelessServerTransport implements McpStatelessServerTransp
private volatile boolean isClosing = false;
/**
* Security validator for validating HTTP requests.
*/
private final ServerTransportSecurityValidator securityValidator;
private WebFluxStatelessServerTransport(McpJsonMapper jsonMapper, String mcpEndpoint,
McpTransportContextExtractor<ServerRequest> contextExtractor) {
McpTransportContextExtractor<ServerRequest> contextExtractor,
ServerTransportSecurityValidator securityValidator) {
Assert.notNull(jsonMapper, "jsonMapper must not be null");
Assert.notNull(mcpEndpoint, "mcpEndpoint must not be null");
Assert.notNull(contextExtractor, "contextExtractor must not be null");
Assert.notNull(securityValidator, "Security validator must not be null");
this.jsonMapper = jsonMapper;
this.mcpEndpoint = mcpEndpoint;
this.contextExtractor = contextExtractor;
this.securityValidator = securityValidator;
this.routerFunction = RouterFunctions.route()
.GET(this.mcpEndpoint, this::handleGet)
.POST(this.mcpEndpoint, this::handlePost)
@ -96,6 +105,14 @@ public class WebFluxStatelessServerTransport implements McpStatelessServerTransp
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).bodyValue("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).bodyValue(e.getMessage());
}
McpTransportContext transportContext = this.contextExtractor.extract(request);
List<MediaType> acceptHeaders = request.headers().asHttpHeaders().getAccept();
@ -160,6 +177,8 @@ public class WebFluxStatelessServerTransport implements McpStatelessServerTransp
private McpTransportContextExtractor<ServerRequest> contextExtractor = (
serverRequest) -> McpTransportContext.EMPTY;
private ServerTransportSecurityValidator securityValidator = ServerTransportSecurityValidator.NOOP;
private Builder() {
// used by a static method
}
@ -205,6 +224,18 @@ public class WebFluxStatelessServerTransport implements McpStatelessServerTransp
return this;
}
/**
* Sets the security validator for validating HTTP requests.
* @param securityValidator The security validator to use. Must not be null.
* @return this builder instance
* @throws IllegalArgumentException if securityValidator is null
*/
public Builder securityValidator(ServerTransportSecurityValidator securityValidator) {
Assert.notNull(securityValidator, "Security validator must not be null");
this.securityValidator = securityValidator;
return this;
}
/**
* Builds a new instance of {@link WebFluxStatelessServerTransport} with the
* configured settings.
@ -214,7 +245,7 @@ public class WebFluxStatelessServerTransport implements McpStatelessServerTransp
public WebFluxStatelessServerTransport build() {
Assert.notNull(mcpEndpoint, "Message endpoint must be set");
return new WebFluxStatelessServerTransport(jsonMapper == null ? McpJsonMapper.getDefault() : jsonMapper,
mcpEndpoint, contextExtractor);
mcpEndpoint, contextExtractor, securityValidator);
}
}

View file

@ -1,5 +1,5 @@
/*
* Copyright 2025-2025 the original author or authors.
* Copyright 2025-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
@ -36,6 +36,7 @@ import reactor.core.publisher.Mono;
import java.io.IOException;
import java.time.Duration;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
@ -67,17 +68,24 @@ public class WebFluxStreamableServerTransportProvider implements McpStreamableSe
private KeepAliveScheduler keepAliveScheduler;
/**
* Security validator for validating HTTP requests.
*/
private final ServerTransportSecurityValidator securityValidator;
private WebFluxStreamableServerTransportProvider(McpJsonMapper jsonMapper, String mcpEndpoint,
McpTransportContextExtractor<ServerRequest> contextExtractor, boolean disallowDelete,
Duration keepAliveInterval) {
Duration keepAliveInterval, ServerTransportSecurityValidator securityValidator) {
Assert.notNull(jsonMapper, "JsonMapper must not be null");
Assert.notNull(mcpEndpoint, "Message endpoint must not be null");
Assert.notNull(contextExtractor, "Context extractor must not be null");
Assert.notNull(securityValidator, "Security validator must not be null");
this.jsonMapper = jsonMapper;
this.mcpEndpoint = mcpEndpoint;
this.contextExtractor = contextExtractor;
this.disallowDelete = disallowDelete;
this.securityValidator = securityValidator;
this.routerFunction = RouterFunctions.route()
.GET(this.mcpEndpoint, this::handleGet)
.POST(this.mcpEndpoint, this::handlePost)
@ -166,6 +174,14 @@ public class WebFluxStreamableServerTransportProvider implements McpStreamableSe
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).bodyValue("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).bodyValue(e.getMessage());
}
McpTransportContext transportContext = this.contextExtractor.extract(request);
return Mono.defer(() -> {
@ -221,6 +237,14 @@ public class WebFluxStreamableServerTransportProvider implements McpStreamableSe
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).bodyValue("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).bodyValue(e.getMessage());
}
McpTransportContext transportContext = this.contextExtractor.extract(request);
List<MediaType> acceptHeaders = request.headers().asHttpHeaders().getAccept();
@ -310,6 +334,14 @@ public class WebFluxStreamableServerTransportProvider implements McpStreamableSe
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).bodyValue("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).bodyValue(e.getMessage());
}
McpTransportContext transportContext = this.contextExtractor.extract(request);
return Mono.defer(() -> {
@ -410,6 +442,8 @@ public class WebFluxStreamableServerTransportProvider implements McpStreamableSe
private Duration keepAliveInterval;
private ServerTransportSecurityValidator securityValidator = ServerTransportSecurityValidator.NOOP;
private Builder() {
// used by a static method
}
@ -477,6 +511,18 @@ public class WebFluxStreamableServerTransportProvider implements McpStreamableSe
return this;
}
/**
* Sets the security validator for validating HTTP requests.
* @param securityValidator The security validator to use. Must not be null.
* @return this builder instance
* @throws IllegalArgumentException if securityValidator is null
*/
public Builder securityValidator(ServerTransportSecurityValidator securityValidator) {
Assert.notNull(securityValidator, "Security validator must not be null");
this.securityValidator = securityValidator;
return this;
}
/**
* Builds a new instance of {@link WebFluxStreamableServerTransportProvider} with
* the configured settings.
@ -487,7 +533,7 @@ public class WebFluxStreamableServerTransportProvider implements McpStreamableSe
Assert.notNull(mcpEndpoint, "Message endpoint must be set");
return new WebFluxStreamableServerTransportProvider(
jsonMapper == null ? McpJsonMapper.getDefault() : jsonMapper, mcpEndpoint, contextExtractor,
disallowDelete, keepAliveInterval);
disallowDelete, keepAliveInterval, securityValidator);
}
}

View file

@ -0,0 +1,291 @@
/*
* Copyright 2026-2026 the original author or authors.
*/
package io.modelcontextprotocol.security;
import java.time.Duration;
import java.util.stream.Stream;
import io.modelcontextprotocol.client.McpClient;
import io.modelcontextprotocol.client.McpSyncClient;
import io.modelcontextprotocol.client.transport.WebClientStreamableHttpTransport;
import io.modelcontextprotocol.client.transport.WebFluxSseClientTransport;
import io.modelcontextprotocol.json.McpJsonMapper;
import io.modelcontextprotocol.server.McpServer;
import io.modelcontextprotocol.server.TestUtil;
import io.modelcontextprotocol.server.transport.DefaultServerTransportSecurityValidator;
import io.modelcontextprotocol.server.transport.WebFluxSseServerTransportProvider;
import io.modelcontextprotocol.server.transport.WebFluxStatelessServerTransport;
import io.modelcontextprotocol.server.transport.WebFluxStreamableServerTransportProvider;
import io.modelcontextprotocol.spec.McpSchema;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.BeforeParameterizedClassInvocation;
import org.junit.jupiter.params.Parameter;
import org.junit.jupiter.params.ParameterizedClass;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;
import reactor.core.publisher.Mono;
import reactor.netty.DisposableServer;
import reactor.netty.http.server.HttpServer;
import org.springframework.http.server.reactive.HttpHandler;
import org.springframework.http.server.reactive.ReactorHttpHandlerAdapter;
import org.springframework.web.reactive.function.client.ClientRequest;
import org.springframework.web.reactive.function.client.ClientResponse;
import org.springframework.web.reactive.function.client.ExchangeFilterFunction;
import org.springframework.web.reactive.function.client.ExchangeFunction;
import org.springframework.web.reactive.function.client.WebClient;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.RouterFunctions;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;
import static org.junit.jupiter.api.Named.named;
import static org.junit.jupiter.params.provider.Arguments.arguments;
/**
* Test the header security validation for all transport types.
*
* @author Daniel Garnier-Moiroux
*/
@ParameterizedClass
@MethodSource("transports")
public class WebFluxServerTransportSecurityIntegrationTests {
private static final String DISALLOWED_ORIGIN = "https://malicious.example.com";
@Parameter
private static Transport transport;
private static DisposableServer httpServer;
private static String baseUrl;
@BeforeParameterizedClassInvocation
static void createTransportAndStartServer(Transport transport) {
var port = TestUtil.findAvailablePort();
baseUrl = "http://localhost:" + port;
startServer(transport.routerFunction(), port);
}
@AfterAll
static void afterAll() {
stopServer();
}
private McpSyncClient mcpClient;
private final TestOriginHeaderExchangeFilterFunction exchangeFilterFunction = new TestOriginHeaderExchangeFilterFunction();
@BeforeEach
void setUp() {
mcpClient = transport.createMcpClient(baseUrl, exchangeFilterFunction);
}
@AfterEach
void tearDown() {
mcpClient.close();
}
@Test
void originAllowed() {
exchangeFilterFunction.setOriginHeader(baseUrl);
var result = mcpClient.initialize();
var tools = mcpClient.listTools();
assertThat(result.protocolVersion()).isNotEmpty();
assertThat(tools.tools()).isEmpty();
}
@Test
void noOrigin() {
exchangeFilterFunction.setOriginHeader(null);
var result = mcpClient.initialize();
var tools = mcpClient.listTools();
assertThat(result.protocolVersion()).isNotEmpty();
assertThat(tools.tools()).isEmpty();
}
@Test
void connectOriginNotAllowed() {
exchangeFilterFunction.setOriginHeader(DISALLOWED_ORIGIN);
assertThatThrownBy(() -> mcpClient.initialize());
}
@Test
void messageOriginNotAllowed() {
exchangeFilterFunction.setOriginHeader(baseUrl);
mcpClient.initialize();
exchangeFilterFunction.setOriginHeader(DISALLOWED_ORIGIN);
assertThatThrownBy(() -> mcpClient.listTools());
}
// ----------------------------------------------------
// Server management
// ----------------------------------------------------
private static void startServer(RouterFunction<?> routerFunction, int port) {
HttpHandler httpHandler = RouterFunctions.toHttpHandler(routerFunction);
ReactorHttpHandlerAdapter adapter = new ReactorHttpHandlerAdapter(httpHandler);
httpServer = HttpServer.create().port(port).handle(adapter).bindNow();
}
private static void stopServer() {
if (httpServer != null) {
httpServer.disposeNow();
}
}
// ----------------------------------------------------
// Transport servers to test
// ----------------------------------------------------
/**
* All transport types we want to test. We use a {@link MethodSource} rather than a
* {@link org.junit.jupiter.params.provider.ValueSource} to provide a readable name.
*/
static Stream<Arguments> transports() {
//@formatter:off
return Stream.of(
arguments(named("SSE", new Sse())),
arguments(named("Streamable HTTP", new StreamableHttp())),
arguments(named("Stateless", new Stateless()))
);
//@formatter:on
}
/**
* Represents a server transport we want to test, and how to create a client for the
* resulting MCP Server.
*/
interface Transport {
McpSyncClient createMcpClient(String baseUrl, TestOriginHeaderExchangeFilterFunction customizer);
RouterFunction<?> routerFunction();
}
/**
* SSE-based transport.
*/
static class Sse implements Transport {
private final WebFluxSseServerTransportProvider transportProvider;
public Sse() {
transportProvider = WebFluxSseServerTransportProvider.builder()
.messageEndpoint("/mcp/message")
.securityValidator(
DefaultServerTransportSecurityValidator.builder().allowedOrigin("http://localhost:*").build())
.build();
McpServer.sync(transportProvider)
.serverInfo("test-server", "1.0.0")
.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
.build();
}
@Override
public McpSyncClient createMcpClient(String baseUrl,
TestOriginHeaderExchangeFilterFunction exchangeFilterFunction) {
var transport = WebFluxSseClientTransport
.builder(WebClient.builder().baseUrl(baseUrl).filter(exchangeFilterFunction))
.jsonMapper(McpJsonMapper.getDefault())
.build();
return McpClient.sync(transport).initializationTimeout(Duration.ofMillis(500)).build();
}
@Override
public RouterFunction<?> routerFunction() {
return transportProvider.getRouterFunction();
}
}
static class StreamableHttp implements Transport {
private final WebFluxStreamableServerTransportProvider transportProvider;
public StreamableHttp() {
transportProvider = WebFluxStreamableServerTransportProvider.builder()
.securityValidator(
DefaultServerTransportSecurityValidator.builder().allowedOrigin("http://localhost:*").build())
.build();
McpServer.sync(transportProvider)
.serverInfo("test-server", "1.0.0")
.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
.build();
}
@Override
public McpSyncClient createMcpClient(String baseUrl,
TestOriginHeaderExchangeFilterFunction exchangeFilterFunction) {
var transport = WebClientStreamableHttpTransport
.builder(WebClient.builder().baseUrl(baseUrl).filter(exchangeFilterFunction))
.jsonMapper(McpJsonMapper.getDefault())
.openConnectionOnStartup(true)
.build();
return McpClient.sync(transport).initializationTimeout(Duration.ofMillis(500)).build();
}
@Override
public RouterFunction<?> routerFunction() {
return transportProvider.getRouterFunction();
}
}
static class Stateless implements Transport {
private final WebFluxStatelessServerTransport transportProvider;
public Stateless() {
transportProvider = WebFluxStatelessServerTransport.builder()
.securityValidator(
DefaultServerTransportSecurityValidator.builder().allowedOrigin("http://localhost:*").build())
.build();
McpServer.sync(transportProvider)
.serverInfo("test-server", "1.0.0")
.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
.build();
}
@Override
public McpSyncClient createMcpClient(String baseUrl,
TestOriginHeaderExchangeFilterFunction exchangeFilterFunction) {
var transport = WebClientStreamableHttpTransport
.builder(WebClient.builder().baseUrl(baseUrl).filter(exchangeFilterFunction))
.jsonMapper(McpJsonMapper.getDefault())
.openConnectionOnStartup(true)
.build();
return McpClient.sync(transport).initializationTimeout(Duration.ofMillis(500)).build();
}
@Override
public RouterFunction<?> routerFunction() {
return transportProvider.getRouterFunction();
}
}
static class TestOriginHeaderExchangeFilterFunction implements ExchangeFilterFunction {
private String origin = null;
public void setOriginHeader(String origin) {
this.origin = origin;
}
@Override
public Mono<ClientResponse> filter(ClientRequest request, ExchangeFunction next) {
var updatedRequest = ClientRequest.from(request).header("origin", this.origin).build();
return next.exchange(updatedRequest);
}
}
}

View file

@ -1,5 +1,5 @@
/*
* Copyright 2024-2024 the original author or authors.
* Copyright 2024-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
@ -7,6 +7,7 @@ package io.modelcontextprotocol.server.transport;
import java.io.IOException;
import java.time.Duration;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.locks.ReentrantLock;
@ -118,6 +119,11 @@ public class WebMvcSseServerTransportProvider implements McpServerTransportProvi
private KeepAliveScheduler keepAliveScheduler;
/**
* Security validator for validating HTTP requests.
*/
private final ServerTransportSecurityValidator securityValidator;
/**
* Constructs a new WebMvcSseServerTransportProvider instance.
* @param jsonMapper The McpJsonMapper to use for JSON serialization/deserialization
@ -131,22 +137,26 @@ public class WebMvcSseServerTransportProvider implements McpServerTransportProvi
* @param keepAliveInterval The interval for sending keep-alive messages to clients.
* @param contextExtractor The contextExtractor to fill in a
* {@link McpTransportContext}.
* @param securityValidator The security validator for validating HTTP requests.
* @throws IllegalArgumentException if any parameter is null
*/
private WebMvcSseServerTransportProvider(McpJsonMapper jsonMapper, String baseUrl, String messageEndpoint,
String sseEndpoint, Duration keepAliveInterval,
McpTransportContextExtractor<ServerRequest> contextExtractor) {
McpTransportContextExtractor<ServerRequest> contextExtractor,
ServerTransportSecurityValidator securityValidator) {
Assert.notNull(jsonMapper, "McpJsonMapper must not be null");
Assert.notNull(baseUrl, "Message base URL must not be null");
Assert.notNull(messageEndpoint, "Message endpoint must not be null");
Assert.notNull(sseEndpoint, "SSE endpoint must not be null");
Assert.notNull(contextExtractor, "Context extractor must not be null");
Assert.notNull(securityValidator, "Security validator must not be null");
this.jsonMapper = jsonMapper;
this.baseUrl = baseUrl;
this.messageEndpoint = messageEndpoint;
this.sseEndpoint = sseEndpoint;
this.contextExtractor = contextExtractor;
this.securityValidator = securityValidator;
this.routerFunction = RouterFunctions.route()
.GET(this.sseEndpoint, this::handleSseConnection)
.POST(this.messageEndpoint, this::handleMessage)
@ -255,6 +265,14 @@ public class WebMvcSseServerTransportProvider implements McpServerTransportProvi
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).body("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).body(e.getMessage());
}
// Send initial endpoint event
return ServerResponse.sse(sseBuilder -> {
WebMvcMcpSessionTransport sessionTransport = new WebMvcMcpSessionTransport(sseBuilder);
@ -313,6 +331,14 @@ public class WebMvcSseServerTransportProvider implements McpServerTransportProvi
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).body("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).body(e.getMessage());
}
if (request.param(SESSION_ID).isEmpty()) {
return ServerResponse.badRequest().body(new McpError("Session ID missing in message endpoint"));
}
@ -474,6 +500,8 @@ public class WebMvcSseServerTransportProvider implements McpServerTransportProvi
private McpTransportContextExtractor<ServerRequest> contextExtractor = (
serverRequest) -> McpTransportContext.EMPTY;
private ServerTransportSecurityValidator securityValidator = ServerTransportSecurityValidator.NOOP;
/**
* Sets the JSON object mapper to use for message serialization/deserialization.
* @param jsonMapper The object mapper to use
@ -549,6 +577,18 @@ public class WebMvcSseServerTransportProvider implements McpServerTransportProvi
return this;
}
/**
* Sets the security validator for validating HTTP requests.
* @param securityValidator The security validator to use. Must not be null.
* @return this builder instance
* @throws IllegalArgumentException if securityValidator is null
*/
public Builder securityValidator(ServerTransportSecurityValidator securityValidator) {
Assert.notNull(securityValidator, "Security validator must not be null");
this.securityValidator = securityValidator;
return this;
}
/**
* Builds a new instance of WebMvcSseServerTransportProvider with the configured
* settings.
@ -560,7 +600,7 @@ public class WebMvcSseServerTransportProvider implements McpServerTransportProvi
throw new IllegalStateException("MessageEndpoint must be set");
}
return new WebMvcSseServerTransportProvider(jsonMapper == null ? McpJsonMapper.getDefault() : jsonMapper,
baseUrl, messageEndpoint, sseEndpoint, keepAliveInterval, contextExtractor);
baseUrl, messageEndpoint, sseEndpoint, keepAliveInterval, contextExtractor, securityValidator);
}
}

View file

@ -1,5 +1,5 @@
/*
* Copyright 2024-2024 the original author or authors.
* Copyright 2024-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
@ -24,6 +24,7 @@ import reactor.core.publisher.Mono;
import java.io.IOException;
import java.util.List;
import java.util.Map;
/**
* Implementation of a WebMVC based {@link McpStatelessServerTransport}.
@ -50,15 +51,23 @@ public class WebMvcStatelessServerTransport implements McpStatelessServerTranspo
private volatile boolean isClosing = false;
/**
* Security validator for validating HTTP requests.
*/
private final ServerTransportSecurityValidator securityValidator;
private WebMvcStatelessServerTransport(McpJsonMapper jsonMapper, String mcpEndpoint,
McpTransportContextExtractor<ServerRequest> contextExtractor) {
McpTransportContextExtractor<ServerRequest> contextExtractor,
ServerTransportSecurityValidator securityValidator) {
Assert.notNull(jsonMapper, "jsonMapper must not be null");
Assert.notNull(mcpEndpoint, "mcpEndpoint must not be null");
Assert.notNull(contextExtractor, "contextExtractor must not be null");
Assert.notNull(securityValidator, "Security validator must not be null");
this.jsonMapper = jsonMapper;
this.mcpEndpoint = mcpEndpoint;
this.contextExtractor = contextExtractor;
this.securityValidator = securityValidator;
this.routerFunction = RouterFunctions.route()
.GET(this.mcpEndpoint, this::handleGet)
.POST(this.mcpEndpoint, this::handlePost)
@ -100,6 +109,14 @@ public class WebMvcStatelessServerTransport implements McpStatelessServerTranspo
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).body("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).body(e.getMessage());
}
McpTransportContext transportContext = this.contextExtractor.extract(request);
List<MediaType> acceptHeaders = request.headers().asHttpHeaders().getAccept();
@ -179,6 +196,8 @@ public class WebMvcStatelessServerTransport implements McpStatelessServerTranspo
private McpTransportContextExtractor<ServerRequest> contextExtractor = (
serverRequest) -> McpTransportContext.EMPTY;
private ServerTransportSecurityValidator securityValidator = ServerTransportSecurityValidator.NOOP;
private Builder() {
// used by a static method
}
@ -224,6 +243,18 @@ public class WebMvcStatelessServerTransport implements McpStatelessServerTranspo
return this;
}
/**
* Sets the security validator for validating HTTP requests.
* @param securityValidator The security validator to use. Must not be null.
* @return this builder instance
* @throws IllegalArgumentException if securityValidator is null
*/
public Builder securityValidator(ServerTransportSecurityValidator securityValidator) {
Assert.notNull(securityValidator, "Security validator must not be null");
this.securityValidator = securityValidator;
return this;
}
/**
* Builds a new instance of {@link WebMvcStatelessServerTransport} with the
* configured settings.
@ -233,7 +264,7 @@ public class WebMvcStatelessServerTransport implements McpStatelessServerTranspo
public WebMvcStatelessServerTransport build() {
Assert.notNull(mcpEndpoint, "Message endpoint must be set");
return new WebMvcStatelessServerTransport(jsonMapper == null ? McpJsonMapper.getDefault() : jsonMapper,
mcpEndpoint, contextExtractor);
mcpEndpoint, contextExtractor, securityValidator);
}
}

View file

@ -1,5 +1,5 @@
/*
* Copyright 2024-2024 the original author or authors.
* Copyright 2024-2026 the original author or authors.
*/
package io.modelcontextprotocol.server.transport;
@ -7,6 +7,7 @@ package io.modelcontextprotocol.server.transport;
import java.io.IOException;
import java.time.Duration;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.locks.ReentrantLock;
@ -102,6 +103,11 @@ public class WebMvcStreamableServerTransportProvider implements McpStreamableSer
private KeepAliveScheduler keepAliveScheduler;
/**
* Security validator for validating HTTP requests.
*/
private final ServerTransportSecurityValidator securityValidator;
/**
* Constructs a new WebMvcStreamableServerTransportProvider instance.
* @param jsonMapper The McpJsonMapper to use for JSON serialization/deserialization
@ -111,19 +117,26 @@ public class WebMvcStreamableServerTransportProvider implements McpStreamableSer
* @param mcpEndpoint The endpoint URI where clients should send their JSON-RPC
* messages via HTTP. This endpoint will handle GET, POST, and DELETE requests.
* @param disallowDelete Whether to disallow DELETE requests on the endpoint.
* @param contextExtractor The context extractor for transport context from the
* request.
* @param keepAliveInterval The interval for keep-alive pings. If null, no keep-alive
* will be scheduled.
* @param securityValidator The security validator for validating HTTP requests.
* @throws IllegalArgumentException if any parameter is null
*/
private WebMvcStreamableServerTransportProvider(McpJsonMapper jsonMapper, String mcpEndpoint,
boolean disallowDelete, McpTransportContextExtractor<ServerRequest> contextExtractor,
Duration keepAliveInterval) {
Duration keepAliveInterval, ServerTransportSecurityValidator securityValidator) {
Assert.notNull(jsonMapper, "McpJsonMapper must not be null");
Assert.notNull(mcpEndpoint, "MCP endpoint must not be null");
Assert.notNull(contextExtractor, "McpTransportContextExtractor must not be null");
Assert.notNull(securityValidator, "Security validator must not be null");
this.jsonMapper = jsonMapper;
this.mcpEndpoint = mcpEndpoint;
this.disallowDelete = disallowDelete;
this.contextExtractor = contextExtractor;
this.securityValidator = securityValidator;
this.routerFunction = RouterFunctions.route()
.GET(this.mcpEndpoint, this::handleGet)
.POST(this.mcpEndpoint, this::handlePost)
@ -233,6 +246,14 @@ public class WebMvcStreamableServerTransportProvider implements McpStreamableSer
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).body("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).body(e.getMessage());
}
List<MediaType> acceptHeaders = request.headers().asHttpHeaders().getAccept();
if (!acceptHeaders.contains(MediaType.TEXT_EVENT_STREAM)) {
return ServerResponse.badRequest().body("Invalid Accept header. Expected TEXT_EVENT_STREAM");
@ -315,6 +336,14 @@ public class WebMvcStreamableServerTransportProvider implements McpStreamableSer
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).body("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).body(e.getMessage());
}
List<MediaType> acceptHeaders = request.headers().asHttpHeaders().getAccept();
if (!acceptHeaders.contains(MediaType.TEXT_EVENT_STREAM)
|| !acceptHeaders.contains(MediaType.APPLICATION_JSON)) {
@ -427,6 +456,14 @@ public class WebMvcStreamableServerTransportProvider implements McpStreamableSer
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).body("Server is shutting down");
}
try {
Map<String, List<String>> headers = request.headers().asHttpHeaders();
this.securityValidator.validateHeaders(headers);
}
catch (ServerTransportSecurityException e) {
return ServerResponse.status(e.getStatusCode()).body(e.getMessage());
}
if (this.disallowDelete) {
return ServerResponse.status(HttpStatus.METHOD_NOT_ALLOWED).build();
}
@ -609,6 +646,8 @@ public class WebMvcStreamableServerTransportProvider implements McpStreamableSer
private Duration keepAliveInterval;
private ServerTransportSecurityValidator securityValidator = ServerTransportSecurityValidator.NOOP;
/**
* Sets the McpJsonMapper to use for JSON serialization/deserialization of MCP
* messages.
@ -672,6 +711,18 @@ public class WebMvcStreamableServerTransportProvider implements McpStreamableSer
return this;
}
/**
* Sets the security validator for validating HTTP requests.
* @param securityValidator The security validator to use. Must not be null.
* @return this builder instance
* @throws IllegalArgumentException if securityValidator is null
*/
public Builder securityValidator(ServerTransportSecurityValidator securityValidator) {
Assert.notNull(securityValidator, "Security validator must not be null");
this.securityValidator = securityValidator;
return this;
}
/**
* Builds a new instance of {@link WebMvcStreamableServerTransportProvider} with
* the configured settings.
@ -682,7 +733,7 @@ public class WebMvcStreamableServerTransportProvider implements McpStreamableSer
Assert.notNull(this.mcpEndpoint, "MCP endpoint must be set");
return new WebMvcStreamableServerTransportProvider(
jsonMapper == null ? McpJsonMapper.getDefault() : jsonMapper, mcpEndpoint, disallowDelete,
contextExtractor, keepAliveInterval);
contextExtractor, keepAliveInterval, securityValidator);
}
}

View file

@ -0,0 +1,334 @@
/*
* Copyright 2026-2026 the original author or authors.
*/
package io.modelcontextprotocol.security;
import java.net.URI;
import java.net.http.HttpRequest;
import java.time.Duration;
import java.util.stream.Stream;
import io.modelcontextprotocol.client.McpClient;
import io.modelcontextprotocol.client.McpSyncClient;
import io.modelcontextprotocol.client.transport.HttpClientSseClientTransport;
import io.modelcontextprotocol.client.transport.HttpClientStreamableHttpTransport;
import io.modelcontextprotocol.client.transport.customizer.McpSyncHttpClientRequestCustomizer;
import io.modelcontextprotocol.common.McpTransportContext;
import io.modelcontextprotocol.json.McpJsonMapper;
import io.modelcontextprotocol.server.McpServer;
import io.modelcontextprotocol.server.McpStatelessSyncServer;
import io.modelcontextprotocol.server.McpSyncServer;
import io.modelcontextprotocol.server.TestUtil;
import io.modelcontextprotocol.server.TomcatTestUtil;
import io.modelcontextprotocol.server.TomcatTestUtil.TomcatServer;
import io.modelcontextprotocol.server.transport.DefaultServerTransportSecurityValidator;
import io.modelcontextprotocol.server.transport.WebMvcSseServerTransportProvider;
import io.modelcontextprotocol.server.transport.WebMvcStatelessServerTransport;
import io.modelcontextprotocol.server.transport.WebMvcStreamableServerTransportProvider;
import io.modelcontextprotocol.spec.McpSchema;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleState;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.BeforeParameterizedClassInvocation;
import org.junit.jupiter.params.Parameter;
import org.junit.jupiter.params.ParameterizedClass;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.Scope;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.function.RouterFunction;
import org.springframework.web.servlet.function.ServerResponse;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;
import static org.junit.jupiter.api.Named.named;
import static org.junit.jupiter.params.provider.Arguments.arguments;
/**
* Test the header security validation for all transport types.
*
* @author Daniel Garnier-Moiroux
*/
@ParameterizedClass
@MethodSource("transports")
public class ServerTransportSecurityIntegrationTests {
private static final String DISALLOWED_ORIGIN = "https://malicious.example.com";
@Parameter
private static Class<?> configClass;
private static TomcatServer tomcatServer;
private static String baseUrl;
@BeforeParameterizedClassInvocation
static void createTransportAndStartTomcat(Class<?> configClass) {
var port = TestUtil.findAvailablePort();
baseUrl = "http://localhost:" + port;
startTomcat(configClass, port);
}
@AfterAll
static void afterAll() {
stopTomcat();
}
private McpSyncClient mcpClient;
private TestRequestCustomizer requestCustomizer;
@BeforeEach
void setUp() {
mcpClient = tomcatServer.appContext().getBean(McpSyncClient.class);
requestCustomizer = tomcatServer.appContext().getBean(TestRequestCustomizer.class);
}
@AfterEach
void tearDown() {
mcpClient.close();
}
@Test
void originAllowed() {
requestCustomizer.setOriginHeader(baseUrl);
var result = mcpClient.initialize();
var tools = mcpClient.listTools();
assertThat(result.protocolVersion()).isNotEmpty();
assertThat(tools.tools()).isEmpty();
}
@Test
void noOrigin() {
requestCustomizer.setOriginHeader(null);
var result = mcpClient.initialize();
var tools = mcpClient.listTools();
assertThat(result.protocolVersion()).isNotEmpty();
assertThat(tools.tools()).isEmpty();
}
@Test
void connectOriginNotAllowed() {
requestCustomizer.setOriginHeader(DISALLOWED_ORIGIN);
assertThatThrownBy(() -> mcpClient.initialize());
}
@Test
void messageOriginNotAllowed() {
requestCustomizer.setOriginHeader(baseUrl);
mcpClient.initialize();
requestCustomizer.setOriginHeader(DISALLOWED_ORIGIN);
assertThatThrownBy(() -> mcpClient.listTools());
}
// ----------------------------------------------------
// Tomcat management
// ----------------------------------------------------
private static void startTomcat(Class<?> componentClass, int port) {
tomcatServer = TomcatTestUtil.createTomcatServer("", port, componentClass);
try {
tomcatServer.tomcat().start();
assertThat(tomcatServer.tomcat().getServer().getState()).isEqualTo(LifecycleState.STARTED);
}
catch (Exception e) {
throw new RuntimeException("Failed to start Tomcat", e);
}
}
private static void stopTomcat() {
if (tomcatServer != null) {
if (tomcatServer.appContext() != null) {
tomcatServer.appContext().close();
}
if (tomcatServer.tomcat() != null) {
try {
tomcatServer.tomcat().stop();
tomcatServer.tomcat().destroy();
}
catch (LifecycleException e) {
throw new RuntimeException("Failed to stop Tomcat", e);
}
}
}
}
// ----------------------------------------------------
// Transport servers to test
// ----------------------------------------------------
/**
* All transport types we want to test. We use a {@link MethodSource} rather than a
* {@link org.junit.jupiter.params.provider.ValueSource} to provide a readable name.
*/
static Stream<Arguments> transports() {
//@formatter:off
return Stream.of(
arguments(named("SSE", SseConfig.class)),
arguments(named("Streamable HTTP", StreamableHttpConfig.class)),
arguments(named("Stateless", StatelessConfig.class))
);
//@formatter:on
}
// ----------------------------------------------------
// Spring Configuration classes
// ----------------------------------------------------
@Configuration
static class CommonConfig {
@Bean
TestRequestCustomizer requestCustomizer() {
return new TestRequestCustomizer();
}
@Bean
DefaultServerTransportSecurityValidator validator() {
return DefaultServerTransportSecurityValidator.builder().allowedOrigin("http://localhost:*").build();
}
}
@Configuration
@EnableWebMvc
@Import(CommonConfig.class)
static class SseConfig {
@Bean
@Scope("prototype")
McpSyncClient createMcpClient(McpSyncHttpClientRequestCustomizer requestCustomizer) {
var transport = HttpClientSseClientTransport.builder(baseUrl)
.httpRequestCustomizer(requestCustomizer)
.jsonMapper(McpJsonMapper.getDefault())
.build();
return McpClient.sync(transport).initializationTimeout(Duration.ofMillis(500)).build();
}
@Bean
public WebMvcSseServerTransportProvider webMvcSseServerTransport(
DefaultServerTransportSecurityValidator validator) {
return WebMvcSseServerTransportProvider.builder()
.messageEndpoint("/mcp/message")
.securityValidator(validator)
.build();
}
@Bean
public RouterFunction<ServerResponse> routerFunction(WebMvcSseServerTransportProvider transportProvider) {
return transportProvider.getRouterFunction();
}
@Bean
public McpSyncServer mcpServer(WebMvcSseServerTransportProvider transportProvider) {
return McpServer.sync(transportProvider)
.serverInfo("test-server", "1.0.0")
.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
.build();
}
}
@Configuration
@EnableWebMvc
@Import(CommonConfig.class)
static class StreamableHttpConfig {
@Bean
@Scope("prototype")
McpSyncClient createMcpClient(McpSyncHttpClientRequestCustomizer requestCustomizer) {
var transport = HttpClientStreamableHttpTransport.builder(baseUrl)
.httpRequestCustomizer(requestCustomizer)
.jsonMapper(McpJsonMapper.getDefault())
.openConnectionOnStartup(true)
.build();
return McpClient.sync(transport).initializationTimeout(Duration.ofMillis(500)).build();
}
@Bean
public WebMvcStreamableServerTransportProvider webMvcStreamableServerTransport(
DefaultServerTransportSecurityValidator validator) {
return WebMvcStreamableServerTransportProvider.builder().securityValidator(validator).build();
}
@Bean
public RouterFunction<ServerResponse> routerFunction(
WebMvcStreamableServerTransportProvider transportProvider) {
return transportProvider.getRouterFunction();
}
@Bean
public McpSyncServer mcpServer(WebMvcStreamableServerTransportProvider transportProvider) {
return McpServer.sync(transportProvider)
.serverInfo("test-server", "1.0.0")
.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
.build();
}
}
@Configuration
@EnableWebMvc
@Import(CommonConfig.class)
static class StatelessConfig {
@Bean
@Scope("prototype")
McpSyncClient createMcpClient(McpSyncHttpClientRequestCustomizer requestCustomizer) {
var transport = HttpClientStreamableHttpTransport.builder(baseUrl)
.httpRequestCustomizer(requestCustomizer)
.jsonMapper(McpJsonMapper.getDefault())
.openConnectionOnStartup(true)
.build();
return McpClient.sync(transport).initializationTimeout(Duration.ofMillis(500)).build();
}
@Bean
public WebMvcStatelessServerTransport webMvcStatelessServerTransport(
DefaultServerTransportSecurityValidator validator) {
return WebMvcStatelessServerTransport.builder().securityValidator(validator).build();
}
@Bean
public RouterFunction<ServerResponse> routerFunction(WebMvcStatelessServerTransport transportProvider) {
return transportProvider.getRouterFunction();
}
@Bean
public McpStatelessSyncServer mcpStatelessServer(WebMvcStatelessServerTransport transportProvider) {
return McpServer.sync(transportProvider)
.serverInfo("test-server", "1.0.0")
.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
.build();
}
}
static class TestRequestCustomizer implements McpSyncHttpClientRequestCustomizer {
private String originHeader = null;
@Override
public void customize(HttpRequest.Builder builder, String method, URI endpoint, String body,
McpTransportContext context) {
if (originHeader != null) {
builder.header("Origin", originHeader);
}
}
public void setOriginHeader(String originHeader) {
this.originHeader = originHeader;
}
}
}