CVE-2026-98197
Received Received - Intake

Kernel hwmon w83791d sysfs cleanup vulnerability

Publication date: 2026-10-06

Last updated on: 2026-10-06

Assigner: kernel.org

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.

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Meta Information

Published
2026-10-06
Last Modified
2026-10-06
Generated
2026-10-06
AI Q&A
2026-10-06
EPSS Evaluated
N/A
NVD
CVE-2026-98197
EUVD
EUVD-2026-93125

Affected Vendors & Products

Showing 9 associated CPEs
Vendor Product Version / Range
Linux Linux 6e1ecd9b8f1358ed4d099f0c54434240dc40debe
Linux Linux 6e1ecd9b8f1358ed4d099f0c54434240dc40debe
Linux Linux 6e1ecd9b8f1358ed4d099f0c54434240dc40debe
Linux Linux 6e1ecd9b8f1358ed4d099f0c54434240dc40debe
Linux Linux 6e1ecd9b8f1358ed4d099f0c54434240dc40debe
Linux Linux 6e1ecd9b8f1358ed4d099f0c54434240dc40debe
Linux Linux 6e1ecd9b8f1358ed4d099f0c54434240dc40debe
Linux Linux 6e1ecd9b8f1358ed4d099f0c54434240dc40debe
Linux Linux 2.6.28

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves the w83791d hardware monitoring driver. When fan/pwm pins 4-5 are not used as GPIO, the driver creates sysfs files for them during initialization. Normally, these files are removed when the driver is unloaded, but a bug causes them to remain after normal teardown. This leaves stale sysfs files that can access freed driver data, potentially leading to memory corruption or crashes.

Detection Guidance

This vulnerability is specific to the Linux kernel's hwmon subsystem for the w83791d hardware monitoring chip. Detection requires checking if the w83791d driver is loaded and if sysfs files for fan/pwm 4-5 remain after driver unbind. Check loaded modules with 'lsmod | grep w83791d' and inspect sysfs entries under '/sys/bus/i2c/devices/' for stale files.

Impact Analysis

If you use a system with the affected w83791d hardware monitoring driver, this vulnerability could cause system instability or crashes when the driver is unloaded. It may also lead to unexpected behavior if stale sysfs files are accessed after driver teardown, though the risk is limited to systems with specific hardware configurations.

Mitigation Strategies

Update the Linux kernel to a patched version where this issue is resolved. If immediate patching is not possible, unbind and rebind the w83791d driver using 'echo w83791d > /sys/bus/i2c/drivers/w83791d/unbind' followed by 'echo w83791d > /sys/bus/i2c/drivers/w83791d/bind' to clear stale sysfs files.

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