CVE-2026-35041
Last modified
CVE-2026-35041 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.26% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Nearform | Fast-Jwt | >= 5.0.0, < 6.2.1 |
References
- https://github.com/nearform/fast-jwt/pull/595Issue Tracking, Patch
- https://github.com/nearform/fast-jwt/releases/tag/v6.2.1Product, Release Notes
- https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxfExploit, Mitigation, Vendor Advisory
- https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxfExploit, Mitigation, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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