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CVE-2026-35039

CRITICAL CVSS 3.1: 9.1 EPSS 0.02%
Updated Apr 07, 2026
fast-jwt
Parameter Value
CVSS 9.1 (CRITICAL)
Affected Versions before 6.1.0
Type CWE-345 (Insufficient Verification of Data), CWE-706, CWE-1289
Vendor fast-jwt
Public PoC No

fast-jwt provides fast JSON Web Token (JWT) implementation. From 0.0.1 to before 6.1.0, setting up a custom cacheKeyBuilder method which does not properly create unique keys for different tokens can lead to cache collisions. This could cause tokens to be mis-identified during the verification process leading to valid tokens returning claims from different valid tokens and users being mis-identified as other users based on the wrong token.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
None
No disruption

CVSS Vector v3.1