CVE-2026-46204: drm/amdgpu/vcn4: Prevent OOB reads when parsing IB

Synopsis

An out-of-bounds read vulnerability exists in the Linux kernel's amdgpu DRM driver, specifically in the VCN4 component responsible for parsing Indirect Buffers (IBs). The flaw is reachable locally by a low-privilege user with an existing account on the host, requiring no network access or user interaction, as described by the CVSS vector. Successful exploitation allows an attacker to read sensitive memory contents and trigger a system crash, resulting in both information disclosure and a denial of service. A patched-image rebuild is available on HarborGuard for environments running an affected kernel version.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityNot required

  The attacker needs an existing shell or process on the host; no network path to the vulnerable component is required.

• AuthenticationRequired

  Any low-privilege local account is sufficient to reach the vulnerable IB parsing code path in the amdgpu driver.

• Victim interactionNot required

  No action from another user or administrator is needed; the attacker can trigger the bug independently.

• Attack complexityDetail

  Attack complexity is low, meaning the exploit is reliable and requires no special environmental conditions, race wins, or memory-layout dependencies.

Blast Radius

• Reads kernel memory contents that the low-privilege attacker would not normally have access to, which may include in-flight data, session tokens, or other process memory.
• Crashes the affected system or kernel component, forcing a reboot and interrupting all workloads running on that host.
• On a multi-tenant host (for example, a shared Kubernetes node), a crash caused by one container affects every other workload co-located on the same node.