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CVSS 10.0CVSS 10.0 · CRITICAL

CVE-2026-5430Bypass de autenticación en validación de tokens JWT

The JWT authentication mechanism accepts tokens signed with algorithms other than those explicitly configured or supported. This allows an attacker to craft a JWT with an unsupported algorithm, which is then incorrectly validated, leading to unauthorized access. Successful exploitation of this vulnerability may result in unauthorized access to the system, including the potential compromise of administrative accounts and full account takeover. The CVSS score is adjusted to 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) in single-tenant deployments, reflecting that the impact is contained within a single security authority boundary.

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Análisis

Esta vulnerabilidad en el mecanismo de autenticación JWT permite a un atacante falsificar tokens utilizando algoritmos de firma no configurados para saltarse la validación. El impacto directo es el acceso no autorizado y la toma de control total de cuentas, incluyendo perfiles administrativos. Es un riesgo crítico para cualquier aplicación que dependa de JWT para la gestión de identidad y sesiones.

Roles relevantes

BackendFrontendJavascriptTypescriptCyberSecurityJava

Severidad

Puntaje: 10.0(CRITICAL)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
AV: NETWORK
AC: LOW
PR: NONE
UI: NONE
S: CHANGED
C: HIGH
I: HIGH
A: HIGH
Tipo de falla (CWE): CWE-347

EPSS

Probabilidad de explotación (próx. 30 días): 0.0022 (0.2%)
Percentil: 12.9%
EPSS: 2026-08-06

Descripción técnica

The JWT authentication mechanism accepts tokens signed with algorithms other than those explicitly configured or supported. This allows an attacker to craft a JWT with an unsupported algorithm, which is then incorrectly validated, leading to unauthorized access. Successful exploitation of this vulnerability may result in unauthorized access to the system, including the potential compromise of administrative accounts and full account takeover. The CVSS score is adjusted to 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) in single-tenant deployments, reflecting that the impact is contained within a single security authority boundary.

Publicada: 6/8/2026, 8:16:33
Última modificación: 6/8/2026, 15:31:57

Referencias

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