Use the private vulnerability report form of GitHub on this repository. Do not open a public issue for a vulnerability.
Give these details:
- The version or the commit you tested.
- The steps that show the problem.
- The effect of the problem.
The maintainer answers within seven days.
Only the newest release receives security fixes.
The wiki page Threat-Model maps each security requirement of the MCP specification to a module and a test. The file docs/security/tls-review.md records the internal review of the TLS code and its findings. It is also the package for an external reviewer. The defaults of the SDK are secure: the HTTP server binds to 127.0.0.1, validates the Origin header, and seals multi round-trip request state with AES-256-GCM.