drm/amd/display: Fix divide-by-zero in calculate_mcache_setting on zero viewport
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 5 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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)
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.12.114, 6.18.57, 7.1.8, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74449
- 2026-10-03 Alias added: GHSA-2qf4-qh24-m72c
- 2026-10-16 Fix available: Linux/Linux@23a541c31b45fa813b33269376f6bd53535429a8, Linux/[email protected] · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-18 CISA SSVC decision points changed
- 2026-10-21 Fix available: Linux/[email protected], Linux/Linux@70f5f4ddba0d2d89e77ec13b79cdcfbef33be0d9 · CNA
- 2026-10-21 1 new reference · CNA
References
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Sources
- CVE-2026-74449 · CVE Program
- CVE-2026-74449 · NVD
- FIRST EPSS
- GHSA-2qf4-qh24-m72c · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74449 · Red Hat security data · CC BY 4.0
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