ptp: ocp: fix use-after-free bugs causing by ptp_ocp_watchdog
CVE-2025-39859 · published 19 Sept 2025
How serious is it
- Severity: high, CVSS score 7.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2025-39859?
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Who is affected
- Linux Linux: 773bda96492153e11d21eb63ac814669b51fc701 to < e2a6eabe5304a789b7d40ce2576cd80154255e51, 773bda96492153e11d21eb63ac814669b51fc701 to < aad70bdfc8244616e48c434310cab241a3f17781, 773bda96492153e11d21eb63ac814669b51fc701 to < f10d3c7267ac7387a5129d5506c3c5f2460cfd9b, 773bda96492153e11d21eb63ac814669b51fc701 to < 8bf935cf789872350b04c1a6468b0a509f67afb2
- Linux Linux: 5.15
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
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.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/e2a6eabe5304a789b7d40ce2576cd80154255e51
- git.kernel.org/stable/c/aad70bdfc8244616e48c434310cab241a3f17781
- git.kernel.org/stable/c/f10d3c7267ac7387a5129d5506c3c5f2460cfd9b
- git.kernel.org/stable/c/8bf935cf789872350b04c1a6468b0a509f67afb2
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON