IBM ContextForge MCP Gateway is affected by a regular expression denial of service

published 2026-11-13 yesterday modified 2026-11-13 yesterday also EUVD-2026-125806

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits: 0; none known

IBM ContextForge MCP Gateway 1.0.0 through 1.0.11 is potentially vulnerable to denial of service due to uncontrolled regular expression complexity (CWE-400 / ReDoS). An authenticated user with tool-registration privileges can embed catastrophically backtracking regex patterns in a tool's JSON Schema `pattern` field; when ContextForge validates arguments against that schema, the validation call may consume unbounded CPU, potentially degrading gateway availability.

Patch / fix

links 1

ibm.com/support/pages/node/7296667 advisory

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Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-14).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

IBM ContextForge MCP Gateway

Classification

Weakness

CWE-1333 Inefficient Regular Expression Complexity

References

ibm.com /support/pages/node/7296667
vendor-advisory, patch

Sources

CVE List CVE-2026-94407
NVD CVE-2026-94407

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