PYSEC-2026-4298
python-jose algorithm confusion guard bypassed by DER-encoded public keys
At a glance
- Published
- Updated
- CVE
- CVE-2024-33663, CVE-2026-85394
- Aliases
- GHSA-3qf3-8w2g-rqmx, GHSA-6c5p-j8vq-pqhj, PYSEC-2024-232
- CVSS_V3
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CVSS_V4
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
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.
Affected packages
| Package | Versions |
|---|---|
| PyPI · python-jose | introduced 0, last affected 3.5.0 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-85394 ADVISORY
- https://github.com/mpdavis/python-jose/issues/414 WEB
- https://github.com/advisories/GHSA-6c5p-j8vq-pqhj ADVISORY
- https://github.com/mpdavis/python-jose PACKAGE
- https://github.com/mpdavis/python-jose/blob/018b310ddb8b50dcfd09a0c152117835a21dd656/jose/backends/native.py WEB
- https://github.com/mpdavis/python-jose/blob/018b310ddb8b50dcfd09a0c152117835a21dd656/jose/utils.py WEB
- https://www.vulncheck.com/advisories/python-jose-through-3.5.0-algorithm-confusion-via-der-encoded-public-key-as-hmac-secret WEB
- https://pypi.org/project/python-jose PACKAGE
- https://github.com/advisories/GHSA-3qf3-8w2g-rqmx ADVISORY
Sources
| Source | Licence |
|---|---|
| OSV.dev | CC-BY 4.0 — PyPA Advisory Database |