The Linux kernel vulnerability CVE-2026-64524 involves the drm/hyperv driver where a SYNTHVID_RESOLUTION_RESPONSE message with a resolution_count exceeding the supported maximum (64) could lead to out-of-bounds access of the supported_resolution array during parsing. Additionally, when the Windows 10 resolution probe fails, the fallback logic in hyperv_connect_vsp() did not properly populate screen and preferred resolution parameters, causing mode_config dimensions to be zero and resulting in drm_internal_framebuffer_create() rejecting all userspace framebuffer requests with an -EINVAL error. The fix bounds resolution_count against the maximum array size and consolidates fallback logic for Windows 8 and Windows 10 to ensure proper default resolution values are set.

The vulnerability could cause out-of-bounds array access in the kernel, potentially leading to memory corruption or instability. The fallback logic issue could prevent userspace framebuffer creation, impacting graphics functionality under certain conditions. No known exploits in the wild have been reported.

A fix has been implemented in the Linux kernel to validate resolution_count and correct the fallback logic for Windows 8 and Windows 10 resolution probes. Users should update to the patched kernel versions once available. Patch status is not explicitly confirmed here; check the official Linux kernel advisories or distribution updates for the fixed versions and apply them accordingly.