Bug 2542695 (CVE-2026-102272) - CVE-2026-102272 pyjwt: pyjwt: Token forgery via improper Unicode byte-order mark handling
Summary: CVE-2026-102272 pyjwt: pyjwt: Token forgery via improper Unicode byte-order m...
Keywords:
Status: NEW
Alias: CVE-2026-102272
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 20:52 UTC by OSIDB Bzimport
Modified: 2026-09-30 06:56 UTC (History)
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Description OSIDB Bzimport 2026-09-28 20:52:13 UTC 
PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.prepare_key in jwt/algorithms.py is affected because raw-JWK detector does not normalize accepted Unicode byte-order marks before checking for JSON. This occurs when a public JWK is prefixed with a UTF-8 BOM and used in a mixed-algorithm verification path. As a result, public JWK bypasses asymmetric-key detection and becomes the HMAC secret. Consequently, an attacker who knows the public key can forge authenticated tokens. This issue is fixed in version 2.14.0.
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