Vulnerabilities
- CVSS
- 4.7 Medium
- Vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H- EPSS
- 0.12%
- Risk score
- 0.9
- Published
- 2026-02-04
- Status
- Published
In the Linux kernel, the following vulnerability has been resolved:
leds: led-class: Only Add LED to leds_list when it is fully ready
Before this change the LED was added to leds_list before led_init_core()
gets called adding it the list before led_classdev.set_brightness_work gets
initialized.
This leaves a window where led_trigger_register() of a LED's default
trigger will call led_trigger_set() which calls led_set_brightness()
which in turn will end up queueing the *uninitialized*
led_classdev.set_brightness_work.
This race gets hit by the lenovo-thinkpad-t14s EC driver which registers
2 LEDs with a default trigger provided by snd_ctl_led.ko in quick
succession. The first led_classdev_register() causes an async modprobe of
snd_ctl_led to run and that async modprobe manages to exactly hit
the window where the second LED is on the leds_list without led_init_core()
being called for it, resulting in:
------------[ cut here ]------------
WARNING: CPU: 11 PID: 5608 at kernel/workqueue.c:4234 __flush_work+0x344/0x390
Hardware name: LENOVO 21N2S01F0B/21N2S01F0B, BIOS N42ET93W (2.23 ) 09/01/2025
...
Call trace:
__flush_work+0x344/0x390 (P)
flush_work+0x2c/0x50
led_trigger_set+0x1c8/0x340
led_trigger_register+0x17c/0x1c0
led_trigger_register_simple+0x84/0xe8
snd_ctl_led_init+0x40/0xf88 [snd_ctl_led]
do_one_initcall+0x5c/0x318
do_init_module+0x9c/0x2b8
load_module+0x7e0/0x998
Close the race window by moving the adding of the LED to leds_list to
after the led_init_core() call.
A race condition vulnerability was found in the Linux kernel's LED class subsystem. When registering LEDs, the device is added to leds_list before led_init_core() initializes the set_brightness_work workqueue. If a trigger registration occurs during this window, led_set_brightness() attempts to queue an uninitialized work structure, triggering a warning in __flush_work() and potentially causing undefined behavior.
Coverage 3
vulnerability
Multiple vulnerabilities have been discovered in the Linux kernel of Ubuntu. Some of these vulnerabilities allow for privilege escalation, data confidentiality breaches, and data integrity compromise. The vulnerabilities…
vulnerability
Multiple vulnerabilities have been discovered in the Linux kernel of Ubuntu. Some of these vulnerabilities allow for privilege escalation, data confidentiality breaches, and data integrity compromise. These vulnerabiliti…
threat-intel
Multiple vulnerabilities have been discovered in the Linux kernel of Ubuntu. Some of these vulnerabilities allow for privilege escalation, data confidentiality breaches, and denial of service attacks. The vulnerabilities…
Advisories and references