CVE-2024-50114

Estado: ModificadaAlta (7.8)—

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

KVM: arm64: Unregister redistributor for failed vCPU creation

Alex reports that syzkaller has managed to trigger a use-after-free when tearing down a VM:

Upon closer inspection, it appears that we do not properly tear down the MMIO registration for a vCPU that fails creation late in the game, e.g. a vCPU w/ the same ID already exists in the VM.

It is important to consider the context of commit that introduced this bug by moving the unregistration out of __kvm_vgic_vcpu_destroy(). That change correctly sought to avoid an srcu v. config_lock inversion by breaking up the vCPU teardown into two parts, one guarded by the config_lock.

Leer descripción completaMostrar menos

Fix the use-after-free while avoiding lock inversion by adding a special-cased unregistration to __kvm_vgic_vcpu_destroy(). This is safe because failed vCPUs are torn down outside of the config_lock.

Detalles técnicos trazas, registros y código del informe original

  BUG: KASAN: slab-use-after-free in kvm_put_kvm+0x300/0xe68 virt/kvm/kvm_main.c:5769
  Read of size 8 at addr ffffff801c6890d0 by task syz.3.2219/10758

  CPU: 3 UID: 0 PID: 10758 Comm: syz.3.2219 Not tainted 6.11.0-rc6-dirty #64
  Hardware name: linux,dummy-virt (DT)
  Call trace:
   dump_backtrace+0x17c/0x1a8 arch/arm64/kernel/stacktrace.c:317
   show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:324
   __dump_stack lib/dump_stack.c:93 [inline]
   dump_stack_lvl+0x94/0xc0 lib/dump_stack.c:119
   print_report+0x144/0x7a4 mm/kasan/report.c:377
   kasan_report+0xcc/0x128 mm/kasan/report.c:601
   __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381
   kvm_put_kvm+0x300/0xe68 virt/kvm/kvm_main.c:5769
   kvm_vm_release+0x4c/0x60 virt/kvm/kvm_main.c:1409
   __fput+0x198/0x71c fs/file_table.c:422
   ____fput+0x20/0x30 fs/file_table.c:450
   task_work_run+0x1cc/0x23c kernel/task_work.c:228
   do_notify_resume+0x144/0x1a0 include/linux/resume_user_mode.h:50
   el0_svc+0x64/0x68 arch/arm64/kernel/entry-common.c:169
   el0t_64_sync_handler+0x90/0xfc arch/arm64/kernel/entry-common.c:730
   el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

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: 0.23%
Percentil entre todas las CVEs puntuadas: 12
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 Interpreterexecution75 %

Acceso local (AV:L) sin interacción (UI:N) permite escalada de privilegios (I:H, A:H) en kernel Linux; use-after-free en gestión de vCPU KVM con contexto local puede llevar a ejecución de código.

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
CWE-416

Referencias

JSON original (NVD)

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  "id": "CVE-2024-50114",
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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Unregister redistributor for failed vCPU creation\n\nAlex reports that syzkaller has managed to trigger a use-after-free when\ntearing down a VM:\n\n  BUG: KASAN: slab-use-after-free in kvm_put_kvm+0x300/0xe68 virt/kvm/kvm_main.c:5769\n  Read of size 8 at addr ffffff801c6890d0 by task syz.3.2219/10758\n\n  CPU: 3 UID: 0 PID: 10758 Comm: syz.3.2219 Not tainted 6.11.0-rc6-dirty #64\n  Hardware name: linux,dummy-virt (DT)\n  Call trace:\n   dump_backtrace+0x17c/0x1a8 arch/arm64/kernel/stacktrace.c:317\n   show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:324\n   __dump_stack lib/dump_stack.c:93 [inline]\n   dump_stack_lvl+0x94/0xc0 lib/dump_stack.c:119\n   print_report+0x144/0x7a4 mm/kasan/report.c:377\n   kasan_report+0xcc/0x128 mm/kasan/report.c:601\n   __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381\n   kvm_put_kvm+0x300/0xe68 virt/kvm/kvm_main.c:5769\n   kvm_vm_release+0x4c/0x60 virt/kvm/kvm_main.c:1409\n   __fput+0x198/0x71c fs/file_table.c:422\n   ____fput+0x20/0x30 fs/file_table.c:450\n   task_work_run+0x1cc/0x23c kernel/task_work.c:228\n   do_notify_resume+0x144/0x1a0 include/linux/resume_user_mode.h:50\n   el0_svc+0x64/0x68 arch/arm64/kernel/entry-common.c:169\n   el0t_64_sync_handler+0x90/0xfc arch/arm64/kernel/entry-common.c:730\n   el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598\n\nUpon closer inspection, it appears that we do not properly tear down the\nMMIO registration for a vCPU that fails creation late in the game, e.g.\na vCPU w/ the same ID already exists in the VM.\n\nIt is important to consider the context of commit that introduced this bug\nby moving the unregistration out of __kvm_vgic_vcpu_destroy(). That\nchange correctly sought to avoid an srcu v. config_lock inversion by\nbreaking up the vCPU teardown into two parts, one guarded by the\nconfig_lock.\n\nFix the use-after-free while avoiding lock inversion by adding a\nspecial-cased unregistration to __kvm_vgic_vcpu_destroy(). This is safe\nbecause failed vCPUs are torn down outside of the config_lock."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: KVM: arm64: Anular el registro del redistribuidor en caso de creación fallida de una vCPU. Alex informa que syzkaller ha conseguido activar un use-after-free al desmantelar una máquina virtual: ERROR: KASAN: slab-use-after-free en kvm_put_kvm+0x300/0xe68 virt/kvm/kvm_main.c:5769 Lectura de tamaño 8 en la dirección ffffff801c6890d0 por la tarea syz.3.2219/10758 CPU: 3 UID: 0 PID: 10758 Comm: syz.3.2219 No contaminado 6.11.0-rc6-dirty #64 Nombre del hardware: linux,dummy-virt (DT) Rastreo de llamadas: dump_backtrace+0x17c/0x1a8 arch/arm64/kernel/stacktrace.c:317 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:324 __dump_stack lib/dump_stack.c:93 [en línea] dump_stack_lvl+0x94/0xc0 lib/dump_stack.c:119 print_report+0x144/0x7a4 mm/kasan/report.c:377 kasan_report+0xcc/0x128 mm/kasan/report.c:601 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381 kvm_put_kvm+0x300/0xe68 virt/kvm/kvm_main.c:5769 kvm_vm_release+0x4c/0x60 virt/kvm/kvm_main.c:1409 __fput+0x198/0x71c fs/file_table.c:422 ____fput+0x20/0x30 fs/file_table.c:450 task_work_run+0x1cc/0x23c kernel/task_work.c:228 do_notify_resume+0x144/0x1a0 include/linux/resume_user_mode.h:50 el0_svc+0x64/0x68 arch/arm64/kernel/entry-common.c:169 el0t_64_sync_handler+0x90/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 Tras una inspección más detallada, parece que no eliminamos correctamente el registro MMIO para una vCPU que falla en la creación tarde en el juego, por ejemplo, una vCPU con el mismo ID ya existe en la VM. Es importante considerar el contexto de la confirmación que introdujo este error al mover la anulación del registro fuera de __kvm_vgic_vcpu_destroy(). Ese cambio buscó correctamente evitar una inversión de srcu v. config_lock al dividir el desmontaje de la vCPU en dos partes, una protegida por config_lock. Corrija el use-after-free mientras evita la inversión del bloqueo agregando una anulación del registro con caso especial a __kvm_vgic_vcpu_destroy(). Esto es seguro porque las vCPU fallidas se eliminan fuera de config_lock."
    }
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  "lastModified": "2026-06-17T08:03:37.427",
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