CVE-2026-35041
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 3.1
- 6.5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 17% of CVEs (scores of 2026-10-26)
- CWE
- CWE-1333
- Published
- Modified
- Record from
- the NVD, synced
Affected
- nearform:fast-jwt
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-cjw9-ghj4-fwxf | npm | fast-jwt | >=5.0.0 <6.2.1 | 6.2.1 |
References
- https://github.com/nearform/fast-jwt/commit/b0be0ca161593836a153d5180ca5358ad9b5de94
- https://github.com/nearform/fast-jwt/pull/595
- https://github.com/nearform/fast-jwt/releases/tag/v6.2.1
- https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxf
- https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxf