CVE-2026-35041

4.2 MEDIUM
Published: April 09, 2026 Modified: April 14, 2026
View on NVD

Description

fast-jwt provides fast JSON Web Token (JWT) implementation. From 5.0.0 to 6.2.0, a denial-of-service condition exists in fast-jwt when the allowedAud verification option is configured using a regular expression. Because the aud claim is attacker-controlled and the library evaluates it against the supplied RegExp, a crafted JWT can trigger catastrophic backtracking in the JavaScript regex engine, resulting in significant CPU consumption during verification. This vulnerability is fixed in 6.2.1.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/nearform/fast-jwt/pull/595
Source: security-advisories@github.com
Issue Tracking Patch
https://github.com/nearform/fast-jwt/releases/tag/v6.2.1
Source: security-advisories@github.com
Product Release Notes
https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxf
Source: security-advisories@github.com
Exploit Mitigation Vendor Advisory
https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxf
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Mitigation Vendor Advisory

5 reference(s) from NVD

Quick Stats

CVSS v3 Score
4.2 / 10.0
EPSS (Exploit Probability)
0.0%
9th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

nearform