CVE-2026-102266PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation

Beschreibung

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.

Daten: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Wiedergegeben wie in der Quelle, auf Englisch.

Betroffene Produkte und Versionen

Referenzen und Patches

• https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r ExploitVendor Advisory
• https://github.com/jpadilla/pyjwt/commit/f91ed44dd65baaf457f4b3353ed35e98a753934c Patch
• https://github.com/jpadilla/pyjwt/releases/tag/2.14.0 ProductRelease Notes