CVE-2026-94407

A registered tool schema could consume gateway CPU

IBM · ContextForge MCP Gateway tool schema validation

First documented disclosure · Review checkpoint

Summary

Argument validation permitted regular expressions whose runtime grows disproportionately with input. Gateway CPU could be consumed and other calls delayed.

Severity and exploitation evidence

Medium · 6.5/10 · CVSS 3.1. Severity source.

Exploitation not established: The reviewed advisory does not report malicious exploitation.

Exploitation evidence source

Technical severity is not a measure of observed attacks or of risk to your deployment. Attempts, demonstrations, and successful compromise retain the qualifications in the source.

How the weakness works

Argument validation permitted regular expressions whose runtime grows disproportionately with input.

Conditions required

An authenticated user could register a tool schema and the gateway validated arguments against it.

Potential impact

Gateway CPU could be consumed and other calls delayed.

Affected versions and configurations

1.0.0 through 1.0.11.

Fix and mitigation status

1.1.0.

Practical next steps

Upgrade to 1.1.0 or later and limit who can register schemas.

Operating lesson

Apply execution limits to validation rules supplied with tools.

Evidence and limits

The advisory and CVE record were published on 2026-11-13.

Sources