jpadilla PyJWT up to 2.13.x JWS Loading jwt/api_jws.py PyJWS._load recursion

Summaryinfo

A vulnerability classified as problematic has been found in jpadilla PyJWT up to 2.13.x. This affects the function PyJWS._load of the file jwt/api_jws.py of the component JWS Loading. This manipulation causes recursion. This vulnerability appears as CVE-2026-102265. The attack may be initiated remotely. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in jpadilla PyJWT up to 2.13.x. Affected by this vulnerability is the function PyJWS._load of the file jwt/api_jws.py of the component JWS Loading. The manipulation with an unknown input leads to a recursion vulnerability. The CWE definition for the vulnerability is CWE-674. The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. As an impact it is known to affect availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-102265 since 09/28/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 2.14.0 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• jpadilla

Name

• PyJWT

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13

Website

• Product: https://github.com/jpadilla/pyjwt/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion