Vulnerability Description
python-jose through 3.5.0 fails to properly validate asymmetric keys in HMAC initialization, accepting DER-encoded public keys that lack PEM armor or SSH prefixes. Attackers holding the service's public key can forge HS256 tokens that pass verification when algorithms are not explicitly restricted. This is an incomplete fix for CVE-2024-33663.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://github.com/advisories/GHSA-6c5p-j8vq-pqhj
- https://github.com/mpdavis/python-jose
- https://github.com/mpdavis/python-jose/blob/018b310ddb8b50dcfd09a0c152117835a21d
- https://github.com/mpdavis/python-jose/blob/018b310ddb8b50dcfd09a0c152117835a21d
- https://github.com/mpdavis/python-jose/issues/414
- https://www.vulncheck.com/advisories/python-jose-through-3.5.0-algorithm-confusi
FAQ
What is CVE-2026-85394?
CVE-2026-85394 is a vulnerability with a CVSS score of 9.1 (CRITICAL). python-jose through 3.5.0 fails to properly validate asymmetric keys in HMAC initialization, accepting DER-encoded public keys that lack PEM armor or SSH prefixes. Attackers holding the service's publ...
How severe is CVE-2026-85394?
CVE-2026-85394 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-85394?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.