CVE-2026-63854

A flaw was found in the Linux kernel's AMDGPU driver, specifically within the Video Core Next (VCN) version 3.0 encoder and decoder rings. These rings do not support 64-bit user fence writes. A local user could trigger this by attempting to submit commands with 64-bit user fences, which would result in the rejection of these submissions, effectively causing a denial of service for those specific operations.

This vulnerability is rated as Moderate impact because exploitation requires local access on systems equipped with AMD graphics hardware utilizing VCN 3.0 IP blocks, limiting the blast radius strictly to a local denial of service. The issue does not permit privilege escalation or exposure of confidential memory, as improper fence command processing only disrupts media ring operations. Additionally, enterprise server deployments lacking physical AMD GPU accelerators are 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.

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.