5.3

CVE-2026-35040

Exploit

fast-jwt: Stateful RegExp (/g or /y) causes non-deterministic allowed-claim validation (logical DoS)

fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.2.1, using certain modifiers on RegExp objects in the allowedAud, allowedIss, allowedSub, allowedJti, or allowedNonce options in verify functions can cause certain unintended behaviours. This is because some modifiers are stateful and will cause failures in every second verification attempt regardless of the validity of the token provided. Such modifiers are /g (global matching) and /y (sticky matching). This does NOT allow invalid tokens to be accepted, only for valid tokens to be improperly rejected in some configurations. Instead it causes 50% of valid authentication requests to fail in an alternating pattern. This vulnerability is fixed in 6.2.1.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Nearform ≫ Fast-jwt SwPlatformnode.js Version < 6.2.1
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.38% 0.299
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 5.3 3.9 1.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE-440 Expected Behavior Violation

A feature, API, or function does not perform according to its specification.

CWE-697 Incorrect Comparison

The product compares two entities in a security-relevant context, but the comparison is incorrect, which may lead to resultant weaknesses.

https://github.com/nearform/fast-jwt/commit/18d25904e4617e8753526d1b3ab5a2cccdea726a
Patch
https://github.com/nearform/fast-jwt/pull/593
Patch
Issue Tracking
https://github.com/nearform/fast-jwt/releases/tag/v6.2.1
Product
Release Notes
https://github.com/nearform/fast-jwt/security/advisories/GHSA-3j8v-cgw4-2g6q
Vendor Advisory
Exploit
Mitigation