Linux kernel (drivers/gpu/drm/radeon): The radeon video-encode command-stream parser used an uninitialised stack value

CVSS 6.5CVE-2025-21996Kernel, userspace & hypervisorcurated

Impact

The radeon video-encode command-stream parser used an uninitialised stack value as the size argument when validating a relocation, so a tenant that crafts an encode command stream whose first opcode is the encode command gets the bounds check performed against garbage. That turns the CS parser's relocation validation into a coin flip and opens the door to out-of-bounds buffer access driven entirely from the ioctl.

Who can reach it

A container holding /dev/dri/renderD* on a host with a radeon-class AMD GPU submits a hand-built VCE command stream through the CS ioctl. No privilege beyond the render node; conditional on the radeon driver being loaded and the GPU exposing VCE, so it does not apply to amdgpu-era or NVIDIA nodes.

What to do

Update to a kernel with the fix commits below. Interim: blacklist the radeon module on nodes that do not need it, or drop /dev/dri from untrusted containers on radeon hosts.

References

https://git.kernel.org/stable/c/0effb378ebce52b897f85cd7f828854b8c7cb636 https://git.kernel.org/stable/c/5b4d9d20fd455a97920cf158dd19163b879cf65d https://nvd.nist.gov/vuln/detail/CVE-2025-21996

This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.