GCD AI RADAR
incidents/AIR-2026-1221

CVE-2026-67431: Session Hijacking Vulnerability in MCP Ruby SDK

Attack on AI2 Disclosed vulnerabilityInfrastructure vulnerability

A session ownership validation flaw in the MCP Ruby SDK allows attackers with a stolen session identifier to execute tools within a victim's session. The issue was addressed in version 0.23.0.

disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why

Details

type
Attack on AI
An AI model, agent or AI-powered product was the thing exploited, abused or leaked.
categories
  • Infrastructure vulnerability
    CVEs and advisories in AI frameworks, inference servers, MCP servers, AI developer tools and hosting stacks.
owasp llm top 10
mitre atlas
no technique for these categories
Both rows are derived from the type and categories (OWASP 2025 edition, ATLAS release 2026.09), not classified per record. How
severity
2 · Disclosed vulnerability
CVE or vendor advisory, patched or patchable, no confirmed exploitation.
targets
Framework / tooling
products
mcp gem
incident date
29 Jul 2026
first reported
29 Jul 2026
origin
NVD
Vulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
classifier confidence
0.95 · published at or above 0.80; see the methodology
tags
CVE-2026-67431 · mcp · session-hijacking
record
created 2026-10-18 10:04Z · updated 2026-10-18 10:04Z · json

Sources · 1

  1. 2026-07-29
    CVE-2026-67431: MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients.
    NVD · nvd.nist.gov/vuln/detail/CVE-2026-67431

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