CVE-2026-102265
PyJWT: Uncaught RecursionError in jwt.decode() on deeply nested token header
- State
- Published
- Severity
- 5.3 Medium
- Published
- Sep 28, 2026
- Updated
- Oct 1, 2026
- Reserved
- Sep 28, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.3 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | GitHub_M |
Weaknesses
- CWE-674 Uncontrolled Recursion
Affected Products
| Product | Versions |
|---|---|
pyjwtjpadilla |
|
References
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