CVE-2025-40316

What it actually does

Use-after-free in the Linux kernel drm/mediatek driver due to reference count imbalance on component bind failures and unbind operations, allowing access to freed driver data objects.

Why it matters to the business

May cause kernel crashes, system instability, or potential local privilege escalation on Linux systems using MediaTek DRM graphics hardware, necessitating kernel updates that could require reboots and testing.

How an attack unfolds

An attacker with local access triggers DRM component bind operations that fail or initiates unbind sequences to exploit the retained stale references, leading to use of freed memory objects in the mediatek driver.

How to fix it

Update the Linux kernel to version 6.6.117 or apply the fix from commit a5a896f8315de358a2932e2c23c42d550256046a; for affected packages such as libsixel on Ubuntu 20.04 update to 1.8.2-2.1.

How to confirm the fix worked

Confirm the running kernel version is 6.6.117 or newer and verify the presence of commit a5a896f8315de358a2932e2c23c42d550256046a in the kernel source tree.

Typical attack path

1. Obtain local access on an affected Linux system
2. Trigger graphics or DRM device bind/unbind operations via user-space graphics APIs or driver unload
3. Exploit the resulting reference imbalance to access freed kernel objects

How to detect it

Review kernel logs and dmesg output for use-after-free warnings or crashes referencing drm/mediatek or component bind failures; correlate with device unbind events.

What your security team should do

• Prioritize kernel upgrades on systems with MediaTek DRM hardware
• Test updates in non-production environments before broad deployment
• Monitor kernel logs for mediatek DRM-related oops or warnings during the update window