drm/amd/display: Fix divide-by-zero in calculate_mcache_setting on zero viewport (CVE-2026-74449) | HOL Guard CVE

High · CVSS 7.8CVE-2026-74449

drm/amd/display: Fix divide-by-zero in calculate_mcache_setting on zero viewport

Answer in brief

CVE-2026-74449 records a High severity (CVSS 7.8) vulnerability in drm/amd/display: Fix divide-by-zero in calculate_mcache_setting on zero viewport. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 15, 2026Updated Aug 18, 2026Source checked Sep 29, 2026First seen by HOL Aug 15, 2026Material review Aug 18, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.8
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1f93537881fd22712732a60ad12572a3fd40c0ec \|\| >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f327e389c07cfc3a2f6ff54f6214e1a52d457edc \|\| >=0 <7.1.8	1f93537881fd22712732a60ad12572a3fd40c0ec, f327e389c07cfc3a2f6ff54f6214e1a52d457edc, 7.1.8
Linux/Linuxgeneric	>=70839da6360500a82e4d5f78499284474cbed7c1 <1f93537881fd22712732a60ad12572a3fd40c0ec \|\| >=70839da6360500a82e4d5f78499284474cbed7c1 <f327e389c07cfc3a2f6ff54f6214e1a52d457edc	1f93537881fd22712732a60ad12572a3fd40c0ec, f327e389c07cfc3a2f6ff54f6214e1a52d457edc
Linux/Linuxgeneric	6.11	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 1f93537881fd22712732a60ad12572a3fd40c0ec; Linux/Linux to 1f93537881fd22712732a60ad12572a3fd40c0ec if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 18, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 15, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix divide-by-zero in calculate_mcache_setting on zero viewport If a plane reaches calculate_mcache_setting with a zero-area viewport, calculate_mcache_setting exits early with num_mcaches == 0 and mvmpg_width/height == 0. This will cause a divide-by-zero panic and can also cause an underflow on num_mcaches. Fix this by changing calculate_mcache_setting to bool and adding guards after each calculate_mcache_row_bytes call. If num_mcaches or mvmpg_width/height is zero, return a false. Callers will propagate the failure as a rejected mode, which prevents the panic. (cherry picked from commit 29c0f7c655f47bcbd575ff75e58480df6ec3c9da)

Quoted source text, attributed separately from HOL analysis.