Bug 2542703 (CVE-2026-102265) - CVE-2026-102265 pyjwt: pyjwt: Denial of Service via deeply nested token headers
Summary: CVE-2026-102265 pyjwt: pyjwt: Denial of Service via deeply nested token headers
Keywords:
Status: NEW
Alias: CVE-2026-102265
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-28 21:03 UTC by OSIDB Bzimport
Modified: 2026-09-30 10:51 UTC (History)
112 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-09-28 21:03:19 UTC 
PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, PyJWS._load in jwt/api_jws.py is affected because parser catches ValueError but not RecursionError. This occurs when a deeply nested token header reaches json.loads. As a result, RecursionError escapes the documented PyJWT error hierarchy. Consequently, an unauthenticated malformed token can cause a request-level failure and HTTP 500. This issue is fixed in version 2.14.0.
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