CVE-2026-89585 auxdisplay: charlcd: cancel backlight work on registration failure
A use-after-free vulnerability in the Linux kernel charlcd driver allows attackers to cause denial of service or execute code if backlight flashing is enabled and registration fails.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89585?
CVE-2026-89585 is a high-severity use after free vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
auxdisplay: charlcd: cancel backlight work on registration failure
With CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before charlcd_register() calls misc_register(). If registration fails, the caller frees the charlcd object while delayed work still contains its address.
Add charlcd_deinit() to cancel the delayed work and turn the backlight off. Use it for both registration rollback and normal unregistration.
Which versions are affected by CVE-2026-89585?
How do I fix CVE-2026-89585?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-89585 being exploited?
There is no known exploitation of CVE-2026-89585 in the wild and no public exploit code.
Sources
Also known as AZL-100451, BELL-CVE-2026-89585, DEBIAN-CVE-2026-89585, GHSA-72rp-5pw2-wrgc, UBUNTU-CVE-2026-89585.