CVE-2026-11800

Estado: AnalizadaAlta (8.1)—

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to impersonate any federated user linked to the affected Identity Provider, leading to unauthorized access and potential privilege escalation.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Puntuación base: 8.1

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.30%
Percentil entre todas las CVEs puntuadas: 21
Fecha de la puntuación: 5/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1210 Exploitation of Remote Serviceslateral movement85 %
Impacto principalT1078.004 Cloud Accountsstealth · persistence · privilege escalation · initial access90 %
Impacto secundarioT1068 Exploitation for Privilege Escalationprivilege escalation70 %
Impacto secundarioT1556.001 Domain Controller Authenticationdefense impairment · persistence · credential access75 %

Vulnerabilidad remota (AV:N) con credenciales válidas (PR:L) en servicio de autenticación. Permite falsificar tokens JWT para suplantar usuarios federados y escalar privilegios (C:H, I:H).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Privileged Account Management User Training Threat Intelligence Program Multi-factor Authentication Application Isolation and Sandboxing Exploit Protection

Tecnologías afectadas (1)

Redhat — Build OF Keycloak

CWE

CWE-347
CWE-347

Referencias

JSON original (NVD)

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