CVE-2026-102265 — PyJWT: Uncaught RecursionError in jwt.decode() on deeply nested token header
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 Recur…
Published: 2026-09-28 · CVSS: 5.3 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7