CVE-2026-63851

A flaw was found in the Linux kernel's AMDGPU VCN (Video Core Next) driver. This issue arises because the VCN hardware's encoder and decoder components do not properly handle 64-bit user fence writes. An attacker could trigger this by submitting specific commands, causing the system to reject these submissions and potentially leading to a denial of service, where legitimate operations are prevented.

This vulnerability is rated as Low impact because exploitation requires local authenticated access on systems equipped with specific AMD GPU hardware (VCN 4.0.5 IP blocks), limiting the overall attack surface in standard enterprise server environments. An unprivileged local user could trigger video encoding ring failures, causing command processing to stall and affecting GPU-accelerated tasks without compromising system confidentiality or integrity. Typical Red Hat Enterprise Linux deployments running headless or without AMD graphics accelerators remain unaffected by this flaw.

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.