Linux Kernel CVE-2026-74449

Exploitation requires: (1) local access to the target system with at minimum low privileges (PR:L per CVSS); (2) presence of an AMD GPU with the amdgpu DRM driver loaded and active; (3) the ability to configure display planes through the DRM subsystem, typically requiring membership in the 'video' or 'render' group, or an active graphical session under a Wayland or X11 compositor. The trigger is a zero-area viewport configuration reaching calculate_mcache_setting - this can occur through crafted display mode-setting requests. Exploitation is limited by the need for AMD-specific hardware; systems with Intel, NVIDIA, or no discrete GPU are unaffected. Remote exploitation is not possible without a pre-existing foothold (AV:L). The condition does not require any non-default kernel configuration - the amdgpu driver is loaded by default on AMD GPU systems in all major distributions.

The NVD-assigned CVSS 3.1 score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) rates this as High severity with C:H and I:H, which is aggressive for a divide-by-zero - those metrics presuppose a post-panic exploitation path to kernel code execution, not merely a crash. A:H is certain and well-supported. The C:H and I:H are plausible only if an attacker can leverage the panic to disclose kernel memory or achieve privilege escalation through a more complex exploit chain, which is not confirmed by the available description. EPSS at 0.15% (5th percentile) reflects very low near-term exploitation probability, consistent with a local kernel driver bug requiring specific AMD GPU hardware. The vulnerability is not in CISA KEV and no public exploit code has been identified. The tag 'Information Disclosure' supports at least some confidentiality impact. Real-world risk is substantially lower than raw CVSS suggests: exploitation requires local access, an AMD GPU, and the ability to configure display modes (typically requiring membership in the video/render group or an active Wayland/X11 session). This is a credible denial-of-service for multi-user servers or workstations with AMD GPUs, but not a trivial remote escalation. Patch is available in Linux 7.1.8 and 7.2-rc6, making remediation straightforward.

A low-privileged local user on a Linux system with an AMD GPU creates or requests a display mode with a zero-area viewport through a DRM ioctl or a compositor interface - achievable via crafted Wayland/X11 protocol messages or direct /dev/dri access. The zero-area configuration propagates through the display pipeline into calculate_mcache_setting, which returns with all divisor values set to zero. The kernel then executes a division by zero, triggering a fatal exception and immediate kernel panic, taking down the system. No public exploit code for this specific CVE has been identified at time of analysis.