CVEvulnerability
CVE-2026-67431
8.3 HIGH
Official page ↗
- Status
- Deferred
- Published
- 2026-07-29
- Last modified
- 2026-10-24
- Assigner
- [email protected]
- CVSS 4.0 ([email protected])
- 8.3 HIGH — CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Weaknesses
- CWE-284
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.
Related
Weakness · CWE (1)
- CWE-284 Improper Access Control weakness
References
- https://github.com/modelcontextprotocol/ruby-sdk/commit/35466605319a34e4c7808712ae9bb1ca1afb2356 github.com
- https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0 github.com
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-5p9g-j988-pcwv github.com
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-5p9g-j988-pcwv github.com