CVE-2026-35041
low-risk
Published 2026-04-09
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.
Do I need to act?
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0.03% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
4
CVSS 4.2/10
Medium
NETWORK
/ HIGH complexity
References (5)
19
/ 100
low-risk
Severity
14/34 · Moderate
Exploitability
0/34 · Minimal
Exposure
5/34 · Minimal