CVE-2026-35041 (GCVE-0-2026-35041)
Vulnerability from cvelistv5 – Published: 2026-04-09 14:55 – Updated: 2026-04-09 16:15
VLAI
EPSS
VEX
Title
ReDoS in fast-jwt when using RegExp in allowed* leading to CPU exhaustion during token verification
Summary
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.
Severity
4.2 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-09 16:14 UTC
CWE
- CWE-1333 - Inefficient Regular Expression Complexity
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://github.com/nearform/fast-jwt/security/adv… | x_refsource_CONFIRM |
| https://github.com/nearform/fast-jwt/pull/595 | x_refsource_MISC |
| https://github.com/nearform/fast-jwt/commit/b0be0… | x_refsource_MISC |
| https://github.com/nearform/fast-jwt/releases/tag… | x_refsource_MISC |
Impacted products
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