---
id: CVE-2026-101918
title: PyJWT is a Python implementation of JSON Web Token standards
summary: >-
  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
  attacke…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-248
vendor: jpadilla
product: pyjwt
affected:
  - 'pyjwt >= 2.0.0a1, < 2.15.0'
published: '2026-09-28'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T21:17:13.410'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-101918'
references:
  - url: >-
      https://github.com/jpadilla/pyjwt/commit/5fde08a6cf906aa7698de2d6391d88b73006b17b
    label: security-advisories@github.com
  - url: 'https://github.com/jpadilla/pyjwt/releases/tag/2.15.0'
    label: security-advisories@github.com
  - url: 'https://github.com/jpadilla/pyjwt/security/advisories/GHSA-42vr-xj54-vc7v'
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-28T21:20:54.778Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.