The Linux kernel AMDGPU driver for VCN v2.0 encoder and decoder rings did not support 64-bit user fence writes, but did not properly reject command submissions containing such fences. The vulnerability was addressed by setting the no_user_fence flag for these rings, ensuring that command submissions with user fences are rejected. This change was introduced via a commit cherry-picked into the kernel source, closing the gap in fence handling for these components.

The vulnerability could have allowed improper command submissions involving unsupported 64-bit user fence writes to the VCN encoder and decoder rings, potentially leading to unexpected behavior or instability in the graphics subsystem. However, no known exploits in the wild have been reported.

A fix has been implemented in the Linux kernel by setting the no_user_fence flag for the affected VCN v2.0 encoder and decoder rings. Users should update to a Linux kernel version that includes this patch to mitigate the vulnerability. Patch status is not explicitly confirmed in the provided data; users should verify with the vendor or kernel release notes for the exact fixed versions.