CVE-2026-89823 drm: fix race between partial drm_dev_register() failure and ioctl
A race condition in the Linux kernel DRM subsystem allows userspace to trigger use-after-free during device registration failure, potentially causing crashes or code execution.
- 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-2026-89823?
CVE-2026-89823 is a high-severity vulnerability in Linux, published on 16 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:
drm: fix race between partial drm_dev_register() failure and ioctl
If drm_dev_register() fails after registering a minor (e.g. render minor registered, primary minor fails), userspace could have opened the first minor and entered a drm_dev_enter() critical section. Since the unplugged flag was never set, the ioctl proceeds while the error path tears down device resources.
Fix this by introducing drm_dev_synchronize_unplug(), which sets the unplugged flag and waits for the SRCU barrier, ensuring all in-flight drm_dev_enter() critical sections complete before cleanup proceeds; call it on the error path of drm_dev_register().
Which versions are affected by CVE-2026-89823?
How do I fix CVE-2026-89823?
Apply the vendor's patch.
Is CVE-2026-89823 being exploited?
There is no known exploitation of CVE-2026-89823 in the wild and no public exploit code.
Sources
Also known as AZL-101291, BELL-CVE-2026-89823, DEBIAN-CVE-2026-89823, GHSA-hjv8-5wf8-79gw, UBUNTU-CVE-2026-89823.