Executive brief
The Linux kernel's lg-laptop driver for LG laptop function keys and keyboard backlight had a resource management flaw where LED devices could be accessed even after failed registration or during removal. This could cause kernel crashes or undefined behavior when the keyboard backlight feature fails to initialize or when the system shuts down, potentially affecting system stability on affected LG laptops.
Technical details
This vulnerability is a use-after-free / resource management defect in the platform/x86/lg-laptop.c driver. The root cause is that the WMI event notification callback and the acpi_remove() function could access the kbd_backlight LED device structure without checking if it was successfully registered with the LED subsystem. The fix introduces tracking via a kbd_backlight_available boolean flag and migrates from manual led_classdev_register()/unregister() calls to devm_led_classdev_register(), which leverages the device resource management framework to automatically unregister devices during driver removal. This prevents double-free and use-after-free conditions. No authentication or network access is required; the flaw is triggered during driver initialization failure or system shutdown on affected systems.
Affected products
- Linux Linux Kernel multiple kernel versions (fix applies to multiple -y stable trees)
Timeline
- 2026-09-17: disclosed
- 2026-07-09: patched