CVE-2026-35041
Medium · 4.2CVSS
4.2
EPSS
0.4%
Published
Apr 9, 2026
CISA due date
—
The record
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 packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| npm | fast-jwt | 5.0.0 | 6.2.1 |
Related vulnerabilities
- GHSA-cjw9-ghj4-fwxf fast-jwt has a ReDoS when using RegExp in allowed* leading to CPU exhaustion during token… Same vulnerability
- CVE-2026-44351 fast-jwt provides fast JSON Web Token (JWT) implementation. Also affects fast-jwt
- GHSA-gmvf-9v4p-v8jc fast-jwt: JWT auth bypass due to empty HMAC secret accepted by async key resolver Also affects fast-jwt
- GHSA-3j8v-cgw4-2g6q fast-jwt: Stateful RegExp (/g or /y) causes non-deterministic allowed-claim validation… Also affects fast-jwt
- CVE-2026-35040 fast-jwt provides fast JSON Web Token (JWT) implementation. Also affects fast-jwt
- CVE-2026-35039 fast-jwt provides fast JSON Web Token (JWT) implementation. Also affects fast-jwt
- CVE-2026-35042 fast-jwt provides fast JSON Web Token (JWT) implementation. Also affects fast-jwt
- CVE-2026-34950 fast-jwt provides fast JSON Web Token (JWT) implementation. Also affects fast-jwt