CVE-2026-98197 hwmon: (w83791d) remove fan/pwm 4-5 sysfs group on remove
A use-after-free vulnerability in the Linux kernel w83791d driver allows attackers to access stale memory via sysfs files after driver unbinding.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98197?
CVE-2026-98197 is a high-severity use after free vulnerability in Linux, published on 6 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (w83791d) remove fan/pwm 4-5 sysfs group on remove
When the fan/pwm 4-5 pins are not used as GPIO, w83791d_probe() creates the w83791d_group_fanpwm45 sysfs group on the I2C client device.
The probe error path removes this group when a later initialization step fails, but the normal remove path only removes w83791d_group. As a result, the optional fan/pwm 4-5 sysfs files can remain after the driver is unbound.
The callbacks associated with these files access the driver data, which is devm allocated and released after driver unbind. Leaving the sysfs files behind can therefore result in accesses to stale driver data.
Remove w83791d_group_fanpwm45 during normal teardown as well.
This issue was found by manual code inspection.
Which versions are affected by CVE-2026-98197?
How do I fix CVE-2026-98197?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-98197 being exploited?
There is no known exploitation of CVE-2026-98197 in the wild and no public exploit code.
Sources
Also known as AZL-106203, BELL-CVE-2026-98197, DEBIAN-CVE-2026-98197, GHSA-w8gm-245m-mgrg, UBUNTU-CVE-2026-98197.