SEPTEMBER 20, 2026
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Case File

CVE-2026-67431

HIGH · CVSS 8.3 EPSS 0.29% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-07-29 · Last synced 2026-08-28

CyberRota Analysis

AI-Generated

The MCP Ruby SDK prior to version 0.23.0 is vulnerable due to a flaw in the StreamableHTTPTransport component, which fails to associate a session ID with its owner. This oversight allows an attacker with access to a stolen session ID to execute requests within the victim's session, potentially leading to unauthorized actions. Organizations using this SDK should prioritize upgrading to version 0.23.0 to mitigate the risk of session hijacking.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links
github.com ↗ github.com ↗ github.com ↗

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-67431
Severity
HIGH
CVSS
8.3
EPSS
0.29%

Original NVD 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.