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CVE-2025-39859

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: ptp: ocp: fix use-after-free bugs causing by ptp_ocp_watchdog The ptp_ocp_detach() only shuts down the watchdog timer if it is pending. However, if the timer handler is already running, the timer_delete_sync() is not called. This leads to race conditions where the devlink that contains the ptp_ocp is deallocated while the timer handler is still accessing it, resulting in use-after-free bugs. The following details one of the race scenarios. (thread 1) | (thread 2) ptp_ocp_remove() | ptp_ocp_detach() | ptp_ocp_watchdog() if (timer_pending(&bp->watchdog))| bp = timer_container_of() timer_delete_sync() | | devlink_free(devlink) //free | | bp-> //use Resolve this by unconditionally calling timer_delete_sync() to ensure the timer is reliably deactivated, preventing any access after free.

Severity
HIGH
CVSS score
7.8 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-09-19 16:15:44.867000
Last modified
2026-10-30 13:18:10.767000
View original CVE JSON 
{
  "id": "CVE-2025-39859",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2025-09-19T16:15:44.867",
  "lastModified": "2026-10-30T13:18:10.767",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nptp: ocp: fix use-after-free bugs causing by ptp_ocp_watchdog\n\nThe ptp_ocp_detach() only shuts down the watchdog timer if it is\npending. However, if the timer handler is already running, the\ntimer_delete_sync() is not called. This leads to race conditions\nwhere the devlink that contains the ptp_ocp is deallocated while\nthe timer handler is still accessing it, resulting in use-after-free\nbugs. The following details one of the race scenarios.\n\n(thread 1)                           | (thread 2)\nptp_ocp_remove()                     |\n  ptp_ocp_detach()                   | ptp_ocp_watchdog()\n    if (timer_pending(&bp->watchdog))|   bp = timer_container_of()\n      timer_delete_sync()            |\n                                     |\n  devlink_free(devlink) //free       |\n                                     |   bp-> //use\n\nResolve this by unconditionally calling timer_delete_sync() to ensure\nthe timer is reliably deactivated, preventing any access after free."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nptp: ocp: corregir errores de uso después de liberación causados por ptp_ocp_watchdog\n\nLa función ptp_ocp_detach() solo detiene el temporizador watchdog si está pendiente. Sin embargo, si el gestor del temporizador ya está en ejecución, la función timer_delete_sync() no es llamada. Esto lleva a condiciones de carrera donde el devlink que contiene el ptp_ocp es desasignado mientras el gestor del temporizador todavía lo está accediendo, lo que resulta en errores de uso después de liberación. A continuación se detalla uno de los escenarios de carrera.\n\n(hilo 1)                           | (hilo 2)\nptp_ocp_remove()                     |\n  ptp_ocp_detach()                   | ptp_ocp_watchdog()\n    if (timer_pending(&bp->watchdog))|   bp = timer_container_of()\n      timer_delete_sync()            |\n                                     |\n  devlink_free(devlink) //liberar       |\n                                     |   bp-> //uso\n\nEsto se resuelve llamando incondicionalmente a timer_delete_sync() para asegurar que el temporizador sea desactivado de forma fiable, evitando cualquier acceso después de la liberación."
    }
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