CVE-2026-102265

PyJWT: Uncaught RecursionError in jwt.decode() on deeply nested token header

MEDIUM
5.3
CVSS Score
Published: September 28, 2026 at 08:48 PM UTC
Updated: October 7, 2026 at 08:57 PM UTC
2 products affected across 2 vendorsPyjwtPyjwt

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.3%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.14.0
Affected range stops below 2.14.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/jpadilla/pyjwt/security/advisories/GHSA-8wjv-2p76-3863
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/jpadilla/pyjwt/releases/tag/2.14.0

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-674

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