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.
References
| Link | Resource |
|---|---|
| https://github.com/jpadilla/pyjwt/commit/f91ed44dd65baaf457f4b3353ed35e98a753934c | Patch |
| https://github.com/jpadilla/pyjwt/releases/tag/2.14.0 | Product Release Notes |
| https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r | Exploit Vendor Advisory |
| https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r | Exploit Vendor Advisory |
Configurations
History
07 Oct 2026, 20:55
| Type | Values Removed | Values Added |
|---|---|---|
| First Time |
Pyjwt Project pyjwt
Pyjwt Project |
|
| References | () https://github.com/jpadilla/pyjwt/commit/f91ed44dd65baaf457f4b3353ed35e98a753934c - Patch | |
| References | () https://github.com/jpadilla/pyjwt/releases/tag/2.14.0 - Product, Release Notes | |
| References | () https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r - Exploit, Vendor Advisory | |
| CPE | cpe:2.3:a:pyjwt_project:pyjwt:2.13.0:*:*:*:*:*:*:* |
29 Sep 2026, 20:17
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r - |
28 Sep 2026, 21:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-09-28 21:17
Updated : 2026-10-07 20:55
NVD link : CVE-2026-102266
Mitre link : CVE-2026-102266
CVE.ORG link : CVE-2026-102266
JSON object : View
Products Affected
pyjwt_project
- pyjwt
CWE
CWE-347
Improper Verification of Cryptographic Signature
