[pkg-vuln] CVE-2026-102266 in pyjwt@2.13.0 #893

New Issue

kert · 2026-09-30T06:01:58Z

kert commented

2026-09-30 06:01:58 +00:00

Severity: HIGH
Package: pyjwt @ 2.13.0
Fixed in: 2.14.0

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.

Reference: https://nvd.nist.gov/vuln/detail/CVE-2026-102266

**Severity:** HIGH **Package:** `pyjwt` @ `2.13.0` **Fixed in:** `2.14.0` 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. **Reference:** https://nvd.nist.gov/vuln/detail/CVE-2026-102266

kert added this to the P21: Package Supply Chain — inventory, mirrors, drift, vuln scanning milestone 2026-09-30 06:01:58 +00:00

kert added the quality ci labels 2026-09-30 06:01:58 +00:00

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Reference: homelab/stack#893