VULNERABILITY INTELLIGENCE
CVE-2026-67431
EPSS probability0.36%
CISA KEVNot currently listed
Published2026-07-29
Last modified2026-10-24
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 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.
Weakness classification
- security-advisories@github.com: CWE-284