CVE-2026-68357

What the bug is

When a watchdog governor is unregistered, it updates existing watchdog devices that were using this governor by falling back to `default_gov`. If the governor being unregistered is currently set as `default_gov`, the `default_gov` is never cleared. This leads to 2 use-after-free issues: 1. New watchdog devices registered after this point will inherit the dangling `default_gov`. 2. Existing watchdog devices using the unregistered governor will have their `wdd->gov` reassigned to the dangling `default_gov`. Fix the UAF by clearing `default_gov` if it matches the governor being unregistered.

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/watchdog/watchdog_pretimeout.c

What this is

WATCHDOG DEVICE DRIVERSMAINTAINERS section matched on drivers/watchdog/ · linux-watchdog@vger.kernel.org · Maintained

Kernel module

watchdog

Check it on the machine

grep -wE 'CONFIG_WATCHDOG|CONFIG_WATCHDOG_CORE|CONFIG_WATCHDOG_PRETIMEOUT_GOV' /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 watchdog

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 code. Every release below compiles the affected file into the kernels it ships.

• bookworm, trixie, forky, sid, bookworm · linux-6.12b

b

built in on some flavours, a module on others

Build switches

CONFIG_WATCHDOG, CONFIG_WATCHDOG_CORE, CONFIG_WATCHDOG_PRETIMEOUT_GOV

Reads as

all on means the file is compiled; any one off means it is not.

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

2026-08-10 (2 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.18%, higher than 6.8% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/watchdog

Upstream fixes

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

Introduced	Fixed in	Commit
4.9	5.10.265	b9ae33faa96b
4.9	5.15.216	472ec1e34ff0
4.9	6.1.183	7a2ee3ec6f20
4.9	6.6.148	2e47b91b9b40
4.9	6.12.101	0ca252720f0e
4.9	6.18.42	7d1658b066de
4.9	7.1.6	7993d626983c
4.9	7.2	7362ba0f9c96

Debian advisories