Bug 2542687 (CVE-2026-102271) - CVE-2026-102271 pyjwt: PyJWT: Authentication bypass via acceptance of DER public keys as HMAC secrets
Summary: CVE-2026-102271 pyjwt: PyJWT: Authentication bypass via acceptance of DER pub...
Keywords:
Status: NEW
Alias: CVE-2026-102271
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
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Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-28 20:46 UTC by OSIDB Bzimport
Modified: 2026-09-28 20:52 UTC (History)
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Description OSIDB Bzimport 2026-09-28 20:46:14 UTC 
PyJWT is a Python implementation of JSON Web Token standards. From 2.4.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because asymmetric-key guard relies on textual markers that are absent from DER encoding. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a DER public key as the shared verification key. As a result, PyJWT uses public DER bytes as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.
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