CVE-2026-102266
7.4
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Summary
PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently, forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| jpadilla | pyjwt | >= 2.13.0, < 2.14.0 | affected |
Weaknesses
- CWE-347: CWE-347: Improper Verification of Cryptographic Signature
References
- https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r
- https://github.com/jpadilla/pyjwt/commit/f91ed44dd65baaf457f4b3353ed35e98a753934c
- https://github.com/jpadilla/pyjwt/releases/tag/2.14.0
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