CVE-2026-102265PYSEC-2026-4142GHSA-8WJV-2P76-3863
PyJWT: Uncaught RecursionError in jwt.decode() on deeply nested token header
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 2.14.0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
CISA's decision points: whether it is exploited, whether attacks can be automated, and how much control an attacker gets. Assessed (SSVC 2.0.3).What do these mean? →
- Exploitation: poc
- Automatable: yes
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- jpadilla pyjwt
From 2.13.0 · fixed in 2.14.0
- pyjwtPyPI
From 2.13.0 · fixed in 2.14.0