Vulnerability Description
MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem reads and parses an entire JSON-RPC POST body without a size limit, allowing an unauthenticated remote attacker to exhaust process memory. This issue is fixed in version 0.23.0.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/modelcontextprotocol/ruby-sdk/commit/772e0cb1f9db69312006926e
- https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-h669-8
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-h669-8
FAQ
What is CVE-2026-67432?
CVE-2026-67432 is a vulnerability with a CVSS score of 7.5 (HIGH). MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem reads and parses an entire JSON-R...
How severe is CVE-2026-67432?
CVE-2026-67432 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-67432?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.