PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because HMAC key guard only recognizes top-level public JWK forms and misses container representations. This occurs when an application allows HMAC and asymmetric algorithms and passes a public JWK container as the raw key. As a result, public asymmetric key material is accepted as the HMAC secret. Consequently, an attacker who knows the public key can forge a token with arbitrary authenticated claims. This issue is fixed in version 2.14.0.

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Source ID Title
Github GHSA Github GHSA GHSA-w2cx-738m-mc7w PyJWT accepts public JWK containers as HMAC secrets
Fixes

Solution

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Workaround

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History

Tue, 29 Sep 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Tue, 29 Sep 2026 13:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Mon, 28 Sep 2026 23:15:00 +0000

Type Values Removed Values Added
First Time appeared Jpadilla
Jpadilla pyjwt
Vendors & Products Jpadilla
Jpadilla pyjwt

Mon, 28 Sep 2026 21:00:00 +0000

Type Values Removed Values Added
Description PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because HMAC key guard only recognizes top-level public JWK forms and misses container representations. This occurs when an application allows HMAC and asymmetric algorithms and passes a public JWK container as the raw key. As a result, public asymmetric key material is accepted as the HMAC secret. Consequently, an attacker who knows the public key can forge a token with arbitrary authenticated claims. This issue is fixed in version 2.14.0.
Title PyJWT accepts public JWK containers as HMAC secrets
Weaknesses CWE-347
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-29T13:44:49.200Z

Reserved: 2026-09-28T20:11:16.658Z

Link: CVE-2026-102273

cve-icon Vulnrichment

Updated: 2026-09-29T13:44:31.737Z

cve-icon NVD

Status : Received

Published: 2026-09-28T21:17:15.497

Modified: 2026-09-29T14:17:19.760

Link: CVE-2026-102273

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-28T20:38:28Z

Links: CVE-2026-102273 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-28T23:00:07Z

Weaknesses