Description
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.
Affected products
pyjwt_project: pyjwt
References4
- github.com/jpadilla/pyjwt/security/advisories/GHSA-8wjv-2p76-38… ExploitMitigationVendor Advisory
- github.com/jpadilla/pyjwt/security/advisories/GHSA-8wjv-2p76-38… ExploitMitigationVendor Advisory
- github.com/jpadilla/pyjwt/commit/06573692ebcdec8831c3927513b3e8… Patch
- github.com/jpadilla/pyjwt/releases/tag/2.14.0 ProductRelease Notes
Metrics
- CVSS 3.1
-
5.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - EPSS — exploit probability
- 0% percentile: 28 · as of 9 November 2026
- CWE
- CWE-674
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