Skip to content
CVE PROGRAM SOURCE RECORD4.2 Medium

CVE-2026-35041

ReDoS in fast-jwt when using RegExp in allowed* leading to CPU exhaustion during token verification

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

nearform fast-jwt

  • >= 5.0.0, < 6.2.1affected

References