Bug 2546414 (CVE-2026-98197)

Summary:	CVE-2026-98197 kernel: hwmon: (w83791d) remove fan/pwm 4-5 sysfs group on remove
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's w83791d hardware monitoring driver. This vulnerability allows a local user to cause a Denial of Service (DoS) by triggering a kernel crash. During driver removal, the driver fails to unregister optional sysfs interface files, leaving them accessible after the underlying device data has been released. An unprivileged or local user interacting with these leftover files causes the kernel to access freed memory, resulting in a use-after-free condition.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-06 09:16:59 UTC

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.

Comment 1 Mauro Matteo Cascella 2026-10-08 18:06:00 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98197.mbox