CVE-2026-46218: drm/amdgpu: Add bounds checking to ib_{get,set}_value

Synopsis

This is an out-of-bounds read and write vulnerability in the Linux kernel's amdgpu DRM driver. A local attacker with a low-privilege account can trigger it without any network access or victim interaction, by submitting crafted GPU command buffers that cause the uvd/vce/vcn codec paths to access the Indirect Buffer (IB) at offsets beyond its allocated size. Successful exploitation reads sensitive kernel memory and can crash the affected system. A patched-image rebuild at the fix versions (6.6.140, 6.12.90, and 6.18.32) is available on HarborGuard for affected environments.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityNot required

  The attacker needs an existing shell or process on the host; no network exposure is involved (AV:L).

• AuthenticationRequired

  Any low-privilege local account is sufficient to trigger the vulnerable code path; no admin rights are needed (PR:L).

• Victim interactionNot required

  No user interaction is required; the attacker submits crafted GPU command buffers directly without involving another user (UI:N).

• Attack complexityDetail

  The exploit is reliable and condition-free; no race conditions or special memory layout are required to trigger the out-of-bounds access (AC:L).

Blast Radius

• A successful attacker reads kernel memory contents that the process should not have access to, potentially exposing sensitive data held in kernel space such as pointers, credentials, or other processes' state (C:H).
• The vulnerability does not directly enable writes to arbitrary kernel memory through the IB bounds escape path alone, so data integrity impact is not indicated (I:N).
• The out-of-bounds access can corrupt kernel state or trigger a kernel panic, crashing the system and taking down all workloads running on the affected host (A:H).
• Containers sharing the host kernel are affected equally; a compromised container with GPU access could destabilize the node for all co-resident workloads.