CVE-2022-50095

Estado: ModificadaAlta (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

posix-cpu-timers: Cleanup CPU timers before freeing them during exec

Commit 55e8c8eb2c7b ("posix-cpu-timers: Store a reference to a pid not a task") started looking up tasks by PID when deleting a CPU timer.

When a non-leader thread calls execve, it will switch PIDs with the leader process. Then, as it calls exit_itimers, posix_cpu_timer_del cannot find the task because the timer still points out to the old PID.

That means that armed timers won't be disarmed, that is, they won't be removed from the timerqueue_list. exit_itimers will still release their memory, and when that list is later processed, it leads to a use-after-free.

Leer descripción completaMostrar menos

Clean up the timers from the de-threaded task before freeing them. This prevents a reported use-after-free.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.25%
Percentil entre todas las CVEs puntuadas: 15
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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1059 Command and Scripting Interpreterexecution70 %

Vulnerabilidad local (AV:L, PR:L) de use-after-free en CPU timers del kernel Linux durante execve. Permite ejecución de código con escalada de privilegios desde proceso con permisos limitados.

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

Execution Prevention Threat Intelligence Program Restrict Web-Based Content Privileged Account Management Limit Software Installation Behavior Prevention on Endpoint

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-416

Referencias

JSON original (NVD)

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nposix-cpu-timers: Cleanup CPU timers before freeing them during exec\n\nCommit 55e8c8eb2c7b (\"posix-cpu-timers: Store a reference to a pid not a\ntask\") started looking up tasks by PID when deleting a CPU timer.\n\nWhen a non-leader thread calls execve, it will switch PIDs with the leader\nprocess. Then, as it calls exit_itimers, posix_cpu_timer_del cannot find\nthe task because the timer still points out to the old PID.\n\nThat means that armed timers won't be disarmed, that is, they won't be\nremoved from the timerqueue_list. exit_itimers will still release their\nmemory, and when that list is later processed, it leads to a\nuse-after-free.\n\nClean up the timers from the de-threaded task before freeing them. This\nprevents a reported use-after-free."
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      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: posix-cpu-timers: Limpiar los temporizadores de CPU antes de liberarlos durante la ejecución. el commit 55e8c8eb2c7b (\"posix-cpu-timers: Almacenar una referencia a un PID, no a una tarea\") comenzó a buscar tareas por PID al eliminar un temporizador de CPU. Cuando un subproceso no líder llama a execve, intercambia los PID con el proceso líder. Luego, al llamar a exit_itimers, posix_cpu_timer_del no puede encontrar la tarea porque el temporizador aún apunta al PID anterior. Esto significa que los temporizadores armados no se desarmarán; es decir, no se eliminarán de timerqueue_list. exit_itimers liberará su memoria y, cuando esa lista se procese posteriormente, se generará un Use-After-Free. Limpie los temporizadores de la tarea desprovista de subprocesos antes de liberarlos. Esto evita un Use-After-Free reportado."
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