UNKNOWNCVE-2026-35039

CVE-2026-35039: fast-jwt Cache Collision Vulnerability

Platform

nodejs

Component

fast-jwt

Fixed in

6.1.0

CVE-2026-35039 describes a cache collision vulnerability within the fast-jwt library. Improperly configured cache key builders can lead to tokens being misidentified during verification, potentially resulting in user impersonation, privilege escalation, and cross-tenant data access. This issue affects versions prior to 6.1.0, and is resolved in version 6.1.0.

How to fix

Actualice a la versión 6.1.0 o superior para mitigar el riesgo de confusión de caché. Asegúrese de que el `cacheKeyBuilder` personalizado genere claves de caché únicas para cada token para evitar colisiones y la identificación incorrecta de tokens.

Frequently asked questions

What is CVE-2026-35039?

CVE-2026-35039 is a cache collision vulnerability in the fast-jwt library. It can lead to user impersonation and privilege escalation due to incorrect token verification.

Am I affected by CVE-2026-35039?

You are affected if you are using a version of fast-jwt prior to 6.1.0 and have configured a custom cacheKeyBuilder that does not generate unique keys.

How do I fix CVE-2026-35039?

Upgrade to fast-jwt version 6.1.0 or later. This version includes a fix that prevents cache collisions and ensures proper token verification.

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CVE-2026-35039: fast-jwt Cache Collision Vulnerability | NextGuard