CVE-2026-89821 drm/amd/display: avoid divide-by-zero in __is_lut_linear()
A local attacker can trigger a kernel crash via divide-by-zero in AMD display driver when processing single-entry LUTs.
- 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-2026-89821?
CVE-2026-89821 is a denial of service 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/amd/display: avoid divide-by-zero in __is_lut_linear()
__is_lut_linear() computes the expected value of each entry with
expected = i * MAX_DRM_LUT_VALUE / (size - 1);
If it is ever called with a single-entry LUT, size - 1 is zero and the kernel takes a divide error (#DE). A LUT with fewer than two entries cannot describe a linear mapping anyway, so return false early instead of dividing by zero.
Which versions are affected by CVE-2026-89821?
How do I fix CVE-2026-89821?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-89821 being exploited?
There is no known exploitation of CVE-2026-89821 in the wild and no public exploit code.
Sources
Also known as AZL-101474, BELL-CVE-2026-89821, DEBIAN-CVE-2026-89821, GHSA-4rrm-wvmv-qhx6, UBUNTU-CVE-2026-89821.