CVE-2026-35041

April 9, 2026, 5:16 p.m.

4.2
Medium

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.

Product(s) Impacted

Vendor Product Versions
Fast-jwt
  • Fast-jwt
  • <5.0.0-6.2.0>, 6.2.1

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-1333
Inefficient Regular Expression Complexity
The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a fast-jwt fast-jwt <5.0.0-6.2.0> / / / / / / /
a fast-jwt fast-jwt 6.2.1 / / / / / / /

CVSS Score

4.2 / 10

CVSS Data - 3.1

  • Attack Vector: NETWORK
  • Attack Complexity: HIGH
  • Privileges Required: HIGH
  • Scope: UNCHANGED
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: HIGH
  • CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H

    View Vector String

Timeline

Published: April 9, 2026, 4:16 p.m.
Last Modified: April 9, 2026, 5:16 p.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.