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.
History

Tue, 06 Oct 2026 19:00:00 +0000

Type Values Removed Values Added
First Time appeared Pyjwt Project
Pyjwt Project pyjwt
CPEs cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:*
Vendors & Products Pyjwt Project
Pyjwt Project pyjwt

Tue, 29 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 29 Sep 2026 13:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Mon, 28 Sep 2026 22:30:00 +0000

Type Values Removed Values Added
First Time appeared Jpadilla
Jpadilla pyjwt
Vendors & Products Jpadilla
Jpadilla pyjwt

Mon, 28 Sep 2026 20:45:00 +0000

Type Values Removed Values Added
Description 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.
Title PyJWT: ReDoS vulnerability when calling the `is_pem_format` function.
Weaknesses CWE-1333
References
Metrics cvssV3_1

{'score': 4.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-09-28T20:29:24.479Z

Updated: 2026-09-29T19:36:54.944Z

Reserved: 2026-09-28T20:11:16.658Z

Link: CVE-2026-102270

cve-icon Vulnrichment

Updated: 2026-09-29T19:36:47.026Z

cve-icon NVD

Status : Analyzed

Published: 2026-09-28T21:17:14.943

Modified: 2026-10-06T18:46:19.343

Link: CVE-2026-102270

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-28T20:29:24Z

Links: CVE-2026-102270 - Bugzilla