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

CVE-2026-50258

Gravedad CVSS v3.1:
ALTA
Tipo:
CWE-121 Desbordamiendo de búfer basado en pila (Stack)
Fecha de publicación:
05/06/2026
Última modificación:
05/06/2026

Descripción

*** Pendiente de traducción *** A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has multiple stack buffers sized XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify or clamp non-canonical key types to XkbMaxShiftLevel. A client can change key types to excessive shift levels and trigger stack overflows. This is caused by an incomplete fix of CVE-2025-26597. This may be used to crash the server, or for privilege escalation if the X server runs as root.