Description
PyJWT is a Python implementation of JSON Web Token standards. From 2.0.0a1 until 2.15.0, PyJWT PyJWKClient.get_signing_key_from_jwt is affected because payload parser catches ValueError but not RecursionError. This occurs when an attacker-controlled recursively nested payload reaches json.loads. As a result, documented PyJWT exception handling does not contain the failure. Consequently, an unauthenticated request can raise an exception that may produce an HTTP 500 response. The advisory-defined affected implementation also includes jwt/api_jwt.py, verify_signature=False. This issue is fixed in version 2.15.0.
Affected products
pyjwt_project: pyjwt
References3
- github.com/jpadilla/pyjwt/security/advisories/GHSA-42vr-xj54-vc… ExploitMitigationVendor Advisory
- github.com/jpadilla/pyjwt/commit/5fde08a6cf906aa7698de2d6391d88… Patch
- github.com/jpadilla/pyjwt/releases/tag/2.15.0 ProductRelease Notes
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 36 · as of 9 November 2026
- CWE
- CWE-248
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