AMDGPU VCN Encoder Ring User Fence Write Vulnerability

Executive Summary

This vulnerability in the Linux kernel involves the AMD GPU driver (amdgpu) and its Video Core Next (VCN) component. Specifically, the VCN encoder and decoder rings do not support 64-bit user fence writes, which are used to synchronize command submissions. As a result, the kernel now rejects command submissions that include user fences for VCN v5.0.1 enc rings to prevent potential issues.

Useful 0 Not Useful 0

Detection Guidance

This vulnerability is specific to the Linux kernel's AMDGPU VCN driver and does not have direct network detection methods. Check kernel logs for AMDGPU-related errors or failed CS submissions with user fences using: dmesg | grep -i amdgpu or journalctl -k | grep -i amdgpu. Verify kernel version with uname -a and ensure it includes the fix.

Useful 0 Not Useful 0

Impact Analysis

This vulnerability may cause applications relying on AMD GPU VCN functionality to fail when submitting commands that use user fences. Users might experience crashes, rendering issues, or application errors when using affected software with AMD GPUs.

Useful 0 Not Useful 0

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it pertains to a specific kernel-level issue in AMD GPU drivers. No evidence suggests it impacts data protection, privacy, or security controls required by these regulations.

Useful 0 Not Useful 0

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for this vulnerability. Check with your distribution vendor for available updates addressing CVE-2026-63849.

Useful 0 Not Useful 0