CVE-2026-89819 drm/amd/display: validate plane degamma LUT size for private color prop
A missing size validation in the AMD display driver allows a local attacker to cause a kernel crash via divide-by-zero or out-of-bounds read.
- 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-2026-89819?
CVE-2026-89819 is a high-severity 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: validate plane degamma LUT size for private color prop
Unlike the CRTC degamma path, which is guarded by amdgpu_dm_verify_lut_sizes(), the per-plane degamma LUT size was never validated before use. __set_dm_plane_degamma() passed the user-supplied size straight into __is_lut_linear() and, for a non-linear LUT, into __set_input_tf() -> __drm_lut_to_dc_gamma(), the latter always iterating MAX_COLOR_LUT_ENTRIES entries regardless of the actual LUT size.
A malformed AMD_PLANE_DEGAMMA_LUT blob (e.g. a single entry) could thus trigger a divide-by-zero in __is_lut_linear() or an out-of-bounds read in __drm_lut_to_dc_gamma(). Reject any plane degamma LUT whose size does not match MAX_COLOR_LUT_ENTRIES, mirroring the invariant the code already asserts a few lines below (and which the CRTC path enforces).
The AMD_PLANE_DEGAMMA_LUT property is only exposed on builds with AMD_PRIVATE_COLOR defined.
Which versions are affected by CVE-2026-89819?
How do I fix CVE-2026-89819?
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-2026-89819 being exploited?
There is no known exploitation of CVE-2026-89819 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-89819, DEBIAN-CVE-2026-89819, GHSA-g935-chxq-f255, UBUNTU-CVE-2026-89819.