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Fencer Intel
critical 9.8

CVE-2026-53709 json

MCP Context Forge: Hardcoded default JWT_SECRET_KEY shipped in source and .env.example enables pre-authentication platform admin token forgery

published 4mo ago modified 26d ago also EUVD-2026-98769 , GHSA-m8rv-5m6m-32ff

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository IBM/mcp-context-forge. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

MCP Context Forge is an MCP gateway and administrative platform. Prior to 1.0.2, mcpgateway/config.py and .env.example ship a known JWT_SECRET_KEY, while verify_jwt_token() accepts HS256 tokens signed with that key and get_current_user() creates a platform administrator when the token subject matches PLATFORM_ADMIN_EMAIL and REQUIRE_USER_IN_DB is false. A remote unauthenticated attacker can therefore mint accepted administrator tokens without a database account. While the vulnerable signing key remains configured and the platform-admin bootstrap remains enabled, forged access survives password rotation, account deletion, and session revocation, allowing administrative disclosure, modification, and service disruption. This issue is fixed in version 1.0.2.

Patch / fix

Is CVE-2026-53709 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
26d ago

Exploit prediction

0.60% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • IBM mcp-context-forge

Classification

Weakness
  • CWE-287 Improper Authentication
  • CWE-321 Use of Hard-coded Cryptographic Key
  • CWE-798 Use of Hard-coded Credentials
  • CWE-1188 Initialization of a Resource with an Insecure Default

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of IBM/mcp-context-forge published their own advisory on GitHub. Reviewed sources take precedence over it.