CVE-2026-67431
CVE-2026-67431 updated by NVD
Summary
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 bind a session ID to a session owner, allowing an attacker with a stolen session ID to send tools/call requests that execute in the victim's session. This issue is fixed in version 0.23.0.
Affected packages
| Ecosystem | Package | Affected versions | Fixed versions |
|---|---|---|---|
| RubyGems | mcp | — | 0.23.0 |
Remediation: Upgrade to 0.23.0 or later.
References
Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.
Includes data from the National Vulnerability Database (NIST). NVD data is in the public domain; this page is not endorsed by NIST.
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EPSS scores provided by the FIRST.org Exploit Prediction Scoring System.