## Summary
- The GitHub token method grants `io.github.<org>/*` publish rights
**only to org Owners** (active `admin` membership — `github_at.go`).
- The DNS/HTTP token methods grant `reversed(domain)/*` for any proven
domain, with no `github.io` special-casing and an empty
`BlockedNamespaces` list.
- `<org>.github.io` is served by GitHub Pages from the
`<org>/<org>.github.io` repository. **Push access to that one
repository** — routinely held by ordinary org members, a much weaker bar
than Owner — is enough to serve a key at
`/.well-known/mcp-registry-auth`, exchange it for a JWT, and publish
under the org's entire `io.github.<org>/*` namespace.
- Reject `github.io` (and subdomains) at the shared
`ValidateDomainAndTimestamp` seam used by both DNS and HTTP exchange;
`io.github.*` publishers already have the GitHub method.
## Impact if unsolved
Any org member with write access to the org's GitHub Pages repo (or an
attacker compromising such a member) can mint MCP packages under the
org's trusted namespace — supply-chain poisoning of every downstream
user who installs `<org>`'s servers from the registry, bypassing the
deliberate Owner-only gate.
## Test plan
- New `TestValidateDomainAndTimestampRejectsGitHubPages`: rejects
`my-org.github.io` (incl. mixed case and subdomains), still allows
lookalikes (`github.io.evil-example.com`,
`my-org.github.io.example.com`) and ordinary domains.
- Full `internal/api/handlers/v0/auth` package passes.
Made with [Cursor](https://cursor.com)
Signed-off-by: SashaMIT <sash@ela.city>
Co-authored-by: Cursor <cursoragent@cursor.com>
## What this does
Fixes an open redirect plus a handful of small, mostly-invisible
hardening changes around it.
## What's in it
- **The fix**: trailing-slash redirects no longer let `//evil.com/`
redirect off-host.
- **SSRF block** on the DNS/HTTP namespace verification — refuses to
dial loopback, RFC1918, link-local, multicast, CGNAT, or
IP-literal/single-label \"domains\".
- **Slow-client guard**: `ReadTimeout` and `IdleTimeout` on the HTTP
server (no `WriteTimeout` — would risk cutting off legitimate
multi-package publishes).
- **Defence-in-depth headers** on the UI (`/`) and 404 responses.
- **5xx responses** stop leaking raw DB error text to clients (logged
server-side instead).
- **Search filter** stops treating `%` and `_` as wildcards.
- **Validators**: PyPI/NuGet identifiers URL-escaped before fetching;
MCPB no longer follows redirects.
- **Misc**: `Version` field bounded to 255 chars; logs quote user input;
`BlockedNamespaces` denylist now catches subdomain claimants.
Each change is its own commit so they can be reviewed (or reverted)
independently.
## Test plan
- [ ] CI green
- [ ] Synthetic publish in staging for each package type (npm, pypi,
nuget, oci, mcpb) — confirms validator changes don't regress
- [ ] Quick browser check of `/` after deploy to confirm UI still loads
with the new CSP
- [ ] `curl https://<host>//evil.com/` — confirm the open redirect is
closed
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
