CVE-2026-35041

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

09/04/2026

Last modified:

14/04/2026

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.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H CVSS v3.1 Severity and Metrics:

Base Score: 4.20 MEDIUM
Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): High
User Interaction (UI): Required
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): High