CVE-2026-35041

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.

Weakness classification

• security-advisories@github.com: CWE-1333

Primary references

• security-advisories@github.com — Patch
• security-advisories@github.com — Issue Tracking, Patch
• security-advisories@github.com — Product, Release Notes
• security-advisories@github.com — Exploit, Mitigation, Vendor Advisory
• 134c704f-9b21-4f2e-91b3-4a467353bcc0 — Exploit, Mitigation, Vendor Advisory