CVE-2018-18955

Estado: ModificadaAlta (7)—💥 Exploit

En el kernel de Linux, de las versiones 4.15.x hasta las 4.19.x anteriores a la 4.19.2, map_write() en kernel/user_namespace.c permite el escalado de privilegios debido a que gestiona incorrectamente los espacios de nombre de usuario anidados con más de 5 rangos UID o GID. Un usuario que tenga CAP_SYS_ADMIN en un espacio de nombre de usuario afectado puede omitir los controles de acceso en los recursos fuera del espacio de nombre, tal y como queda demostrado con la lectura de /etc/shadow. Esto ocurre debido a que una transformación ID ocurre correctamente para la dirección namespaced-to-kernel, pero no para la dirección kernel-to-namespaced.

CVSS

Versión: 3.0
Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 7.61%
Percentil entre todas las CVEs puntuadas: 94
Fecha de la puntuación: 9/10/2026

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).

💥 Exploits públicos

Hay código de explotación o plantillas de detección públicos. No es lo mismo que explotación activa confirmada (KEV), pero aumenta el riesgo: parchee con prioridad.

Módulo de Metasploit (exploit fiable y al alcance de cualquiera) · Linux Nested User Namespace idmap Limit Local Privilege Escalation
Publicado en Exploit-DB · Linux Kernel 4.15.x < 4.19.2 - 'map_write() CAP_SYS_ADMIN' Local Privilege Escalation (dbus Method) (4/1/2019)
Publicado en Exploit-DB · Linux Kernel 4.15.x < 4.19.2 - 'map_write() CAP_SYS_ADMIN' Local Privilege Escalation (polkit Method) (4/1/2019)
Publicado en Exploit-DB · Linux - Nested User Namespace idmap Limit Local Privilege Escalation (Metasploit) (29/11/2018)
Publicado en Exploit-DB · Linux Kernel 4.15.x < 4.19.2 - 'map_write() CAP_SYS_ADMIN' Local Privilege Escalation (cron Method) (21/11/2018)
Publicado en Exploit-DB · Linux Kernel 4.15.x < 4.19.2 - 'map_write() CAP_SYS_ADMIN' Local Privilege Escalation (ldpreload Method) (21/11/2018)
Publicado en Exploit-DB · Linux - Broken uid/gid Mapping for Nested User Namespaces (16/11/2018)
Prueba de concepto en GitHub (no verificada) · Lista de pruebas de concepto en GitHub

⚠️ Las pruebas de concepto de GitHub no están verificadas: algunas son falsas o contienen malware. No las ejecute nunca fuera de un laboratorio aislado.

Tecnologías afectadas (2)

Canonical — Ubuntu Linux Linux — Linux Kernel

CWE

CWE-863

Referencias

JSON original (NVD)

Mostrar

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