CVE-2026-102270

MEDIUM 4.4

PyJWT: ReDoS vulnerability when calling the `is_pem_format` function.

CVSS Score

4.4

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-1333
Vendor	jpadilla
Product	pyjwt
Published	Sep 28, 2026

Stay Ahead of the Next One

Get instant alerts for jpadilla pyjwt

Be the first to know when new medium vulnerabilities affecting jpadilla pyjwt are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

High

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

jpadilla / pyjwt

< 2.14.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jwrc-g2q2-pq5p github.com: https://github.com/jpadilla/pyjwt/commit/8b4e233a22206b34ec1186e912e75c0b2396ac07 github.com: https://github.com/jpadilla/pyjwt/releases/tag/2.14.0