CVE-2026-64098

A flaw was found in the Linux kernel's VirtIO GPU (Graphics Processing Unit) driver. The virtio_gpu_cursor_plane_update() and virtio_gpu_resource_flush() functions fail to properly acquire a required lock, which can lead to a race condition. A local user could exploit this vulnerability by triggering a memory allocation failure on the Direct Rendering Manager (DRM) input/output control (ioctl) cursor path. This improper handling of the lock can result in memory corruption, potentially leading to system instability or other undefined behavior.

A race condition in the virtio GPU DRM plane update path can occur because the return value from virtio_gpu_array_lock_resv was ignored. If dma_resv_lock_interruptible returns EINTR or dma_resv_reserve_fences returns ENOMEM, the reservation lock may not be held while the later queue path still calls dma_resv_add_fence. This violates the dma_resv locking contract and can mutate the fence list concurrently with other readers or writers. With lockdep enabled this is reported as a warning, but without lockdep the same condition can corrupt the dma_resv fence list and may crash the kernel. For the CVSS the PR:L is used because a local user or local process with access to the DRM cursor ioctl can reach the affected plane update path, while full administrator privileges are not inherently required in typical graphics or virtual GPU deployments. The issue is not network reachable. Impact is at least local denial of service via kernel warning or crash, and in the paranoid score may include confidentiality and integrity impact because unlocked mutation of a shared kernel list is a plausible memory corruption candidate.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.