Critical severity9.1NVD Advisory· Published Sep 3, 2026· Updated Sep 24, 2026
CVE-2026-85394
CVE-2026-85394
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
python-josePyPI | <= 3.5.0 | — |
Affected products
1- Range: <=3.5.0
Patches
Vulnerability mechanics
References
7- github.com/advisories/GHSA-3qf3-8w2g-rqmxghsaADVISORY
- github.com/advisories/GHSA-6c5p-j8vq-pqhjnvdADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-85394ghsaADVISORY
- github.com/mpdavis/python-jose/blob/018b310ddb8b50dcfd09a0c152117835a21dd656/jose/backends/native.pynvdWEB
- github.com/mpdavis/python-jose/blob/018b310ddb8b50dcfd09a0c152117835a21dd656/jose/utils.pynvdWEB
- github.com/mpdavis/python-jose/issues/414nvdWEB
- www.vulncheck.com/advisories/python-jose-through-3.5.0-algorithm-confusion-via-der-encoded-public-key-as-hmac-secretnvdWEB
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