CVE-2026-93178

What it actually does

Missing bounds check on vddInd and vddcInd indices from VBIOS tables allows out-of-bounds access when indexing into SMU7 voltage lookup tables in the amdgpu powerplay driver.

Why it matters to the business

Local users on affected Linux systems with AMD GPUs can trigger kernel memory corruption or crashes, leading to denial of service or potential information disclosure on graphics hardware.

How an attack unfolds

An attacker with local access supplies or modifies VBIOS-parsed tables containing out-of-range voltage indices; when the driver performs the unchecked table lookup, it reads or writes beyond allocated buffers, enabling memory corruption.

How to fix it

Apply the upstream kernel patch that adds the -EINVAL bounds check on voltage indices; rebuild and deploy updated kernel packages containing the fix for drm/amdgpu/pm/powerplay.

How to confirm the fix worked

Confirm the patch is present by inspecting the amdgpu powerplay source for the added range validation before table indexing; test with crafted VBIOS data that previously triggered the flaw.

Typical attack path

1. Obtain local user access on a Linux system with vulnerable amdgpu driver
2. Prepare or inject VBIOS data with out-of-range vddInd or vddcInd values
3. Trigger powerplay voltage table lookup via graphics or power management operations
4. Exploit resulting out-of-bounds memory access for corruption or disclosure

How to detect it

Review kernel logs for amdgpu powerplay errors or -EINVAL returns during voltage table processing; inspect for unexpected crashes in drm/amdgpu modules after VBIOS parsing.

What your security team should do

• Prioritize kernel updates on all systems using AMD GPUs with SMU7 powerplay support
• Monitor for local privilege-escalation attempts targeting graphics drivers
• Restrict unprivileged local access where feasible until patches are applied