CVE-2026-35040

Published: Apr 09, 2026 Last Modified: Apr 13, 2026
ExploitDB:
Other exploit source:
Google Dorks:
MEDIUM 5,3
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Scope: unchanged
Confidentiality: none
Integrity: none
Availability: low

Description

AI Translation Available

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.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0006
Percentile
0,2th
Updated

EPSS Score Trend (Last 7 Days)

440

Expected Behavior Violation

Draft
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Other
Potential Impacts:
Quality Degradation Varies By Context
Applicable Platforms
Technologies: ICS/OT
View CWE Details
697

Incorrect Comparison

Incomplete
Abstraction: Pillar Structure: Simple
Common Consequences
Security Scopes Affected:
Other
Potential Impacts:
Varies By Context
Applicable Platforms
All platforms may be affected
View CWE Details
https://github.com/nearform/fast-jwt/commit/18d25904e4617e8…
https://github.com/nearform/fast-jwt/commit/18d25904e4617e8753526d1b3ab5a2cccde…
https://github.com/nearform/fast-jwt/pull/593
https://github.com/nearform/fast-jwt/pull/593
https://github.com/nearform/fast-jwt/releases/tag/v6.2.1
https://github.com/nearform/fast-jwt/releases/tag/v6.2.1
https://github.com/nearform/fast-jwt/security/advisories/GH…
https://github.com/nearform/fast-jwt/security/advisories/GHSA-3j8v-cgw4-2g6q