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::StdioTransport and MCP::Client::Stdio in the mcp gem use IO#gets without a byte limit, allowing a peer that sends data without a newline to 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/267b8fa6285453525c81ce43
- https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-7683-3
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-7683-3
FAQ
What is CVE-2026-63119?
CVE-2026-63119 is a vulnerability with a CVSS score of 6.2 (MEDIUM). MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StdioTransport and MCP::Client::Stdio in the mcp gem use IO#gets without...
How severe is CVE-2026-63119?
CVE-2026-63119 has been rated MEDIUM with a CVSS base score of 6.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-63119?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.