CVE-2025-39859

What the bug is

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.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

drivers/ptp/ptp_ocp.c

What this is

OPENCOMPUTE PTP CLOCK DRIVERMAINTAINERS section matched on drivers/ptp/ptp_ocp.c · netdev@vger.kernel.org · Maintained

Kernel module

ptp_ocp

Check it on the machine

grep -w CONFIG_PTP_1588_CLOCK_OCP /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

lsmod | grep -w ptp_ocp

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64, ppc64el/powerpc64le
• trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x
• forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x

M

a module where it is built at all; some flavours do not build it

Build switch

CONFIG_PTP_1588_CLOCK_OCP

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2025-09-19 (13 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.15%, higher than 3.7% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/ptp

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
5.15	6.16.6	f10d3c7267ac
5.15	6.17	8bf935cf7898