---
id: CVE-2026-102270
title: PyJWT is a Python implementation of JSON Web Token standards
summary: >-
  PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0,
  PyJWT is_pem_format is affected because lazy PEM regular expression backtracks
  extensively. This occurs when a certificate-like input contains repeated BEGIN
  …
severity: medium
cvss: 4.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-1333
vendor: jpadilla
product: pyjwt
affected:
  - pyjwt < 2.14.0
published: '2026-09-28'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T21:17:14.943'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-102270'
references:
  - url: >-
      https://github.com/jpadilla/pyjwt/commit/8b4e233a22206b34ec1186e912e75c0b2396ac07
    label: security-advisories@github.com
  - url: 'https://github.com/jpadilla/pyjwt/releases/tag/2.14.0'
    label: security-advisories@github.com
  - url: 'https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jwrc-g2q2-pq5p'
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-28T21:20:54.781Z'
---

## Overview

PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT is_pem_format is affected because lazy PEM regular expression backtracks extensively. This occurs when a certificate-like input contains repeated BEGIN markers without a matching END marker. As a result, is_pem_format performs unbounded backtracking while searching for a PEM end marker. Consequently, an attacker can cause intensive CPU consumption. This issue is fixed in version 2.14.0.

## Remediation

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