Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

CVE-2026-97174

Gravedad CVSS v3.1:
MEDIA
Tipo:
CWE-20 Validación incorrecta de entrada
Fecha de publicación:
05/11/2026
Última modificación:
06/11/2026

Descripción

*** Pendiente de traducción *** A flaw was found in the Client-Initiated Backchannel Authentication (CIBA) implementation of Keycloak. The CIBA endpoint fails to properly validate the sub parameter, allowing it to be stored as an additional request parameter. During the token issuance process, this injected value overwrites the legitimate subject identifier. This allows an attacker to authenticate as themselves but receive security tokens belonging to a different victim user, leading to unauthorized account access.