GHSA-FQ5X-P5VR-M6PG
Vulnerability from github – Published: 2025-09-22 21:30 – Updated: 2025-12-12 21:31In 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.
{
"affected": [],
"aliases": [
"CVE-2025-39859"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-19T16:15:44Z",
"severity": "HIGH"
},
"details": "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(\u0026bp-\u003ewatchdog))| bp = timer_container_of()\n timer_delete_sync() |\n |\n devlink_free(devlink) //free |\n | bp-\u003e //use\n\nResolve this by unconditionally calling timer_delete_sync() to ensure\nthe timer is reliably deactivated, preventing any access after free.",
"id": "GHSA-fq5x-p5vr-m6pg",
"modified": "2025-12-12T21:31:32Z",
"published": "2025-09-22T21:30:18Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39859"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8bf935cf789872350b04c1a6468b0a509f67afb2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f10d3c7267ac7387a5129d5506c3c5f2460cfd9b"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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