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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-102270
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-28 21:17:14 UTC
Updated2026-09-28 21:17:14 UTC
DescriptionPyJWT 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.

Risk And Classification

Primary CVSS: v3.1 4.4 MEDIUM from [email protected]

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

Problem Types: CWE-1333 | CWE-1333 CWE-1333: Inefficient Regular Expression Complexity

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary4.4MEDIUMCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED4.4MEDIUMCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Jpadilla Pyjwt affected < 2.14.0 Not specified

References

ReferenceSourceLinkTags
github.com/jpadilla/pyjwt/security/advisories/GHSA-jwrc-g2q2-pq5p [email protected] github.com
github.com/jpadilla/pyjwt/releases/tag/2.14.0 [email protected] github.com
github.com/jpadilla/pyjwt/commit/8b4e233a22206b34ec1186e912e75c0b2396ac07 [email protected] github.com
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