CVE-2026-35041

MEDIUM EPSS 17.5%
Published Apr 9, 20262mo ago · Modified Jun 17, 20261w ago
6.5 CVSS 3.1
Medium
Find Similar
Published Apr 9, 2026 2mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
6.5
Exploitability
2.8
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
17.5% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-1333

Affected Products 1

VendorProductVersionRange
nearformfast-jwt*≥5.0.0  –  <6.2.1

References 4

  • github.com https://github.com/nearform/fast-jwt/commit/b0be0ca161593836a153d5180ca5358ad9b5de94
    Patch
  • github.com https://github.com/nearform/fast-jwt/pull/595
    Issue TrackingPatch
  • github.com https://github.com/nearform/fast-jwt/releases/tag/v6.2.1
    ProductRelease Notes
  • github.com https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxf
    ExploitMitigationVendor Advisory

Remediation

  • github.com https://github.com/nearform/fast-jwt/commit/b0be0ca161593836a153d5180ca5358ad9b5de94
    Patch
  • github.com https://github.com/nearform/fast-jwt/pull/595
    Issue TrackingPatch