CVE-2025-40211

In the Linux kernel, the following vulnerability has been resolved:

ACPI: video: Fix use-after-free in acpi_video_switch_brightness()

The switch_brightness_work delayed work accesses device->brightness
and device->backlight, freed by acpi_video_dev_unregister_backlight()
during device removal.

If the work executes after acpi_video_bus_unregister_backlight()
frees these resources, it causes a use-after-free when
acpi_video_switch_brightness() dereferences device->brightness or
device->backlight.

Fix this by calling cancel_delayed_work_sync() for each device's
switch_brightness_work in acpi_video_bus_remove_notify_handler()
after removing the notify handler that queues the work. This ensures
the work completes before the memory is freed.

[ rjw: Changelog edit ]