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 does not expire sessions by default, so repeated initialize requests retain unbounded ServerSession objects and can exhaust process memory. This issue is fixed in version 0.23.0.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/modelcontextprotocol/ruby-sdk/commit/afb968c468c178c4d3294b42
- https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-52jp-g
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-52jp-g
FAQ
What is CVE-2026-67430?
CVE-2026-67430 is a vulnerability with a CVSS score of 5.3 (MEDIUM). 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 does not expire sessions by defau...
How severe is CVE-2026-67430?
CVE-2026-67430 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-67430?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.