CVE-2024-49896

What it actually does

Null pointer dereference in dc_is_stream_unchanged when amdgpu_dm passes a null stream without prior validation, resulting in undefined behavior or kernel crash in the AMD display driver path.

Why it matters to the business

System instability or denial of service on Linux systems with AMD GPUs, leading to unplanned reboots, reduced availability, and operational disruption; low exploitation likelihood limits widespread impact despite kernel prevalence.

How an attack unfolds

An attacker with local access triggers the vulnerable display stream comparison path by supplying a null stream object to dc_is_stream_unchanged, causing the kernel to dereference the null pointer and panic; listed threat actors have targeted similar Linux kernel memory issues but no confirmed exploitation of this specific flaw.

How to fix it

Apply the fix from commit 3944d226f55235a960d8f1135927f95e9801be12 in the Linux kernel; for Rocky Linux 8 systems update zziplib to version 0:0.13.68-8.el8 where applicable.

How to confirm the fix worked

Inspect the dc_is_stream_unchanged function in the updated kernel source to confirm a null check precedes any stream comparison or dereference.

Typical attack path

1. Obtain local access on a vulnerable Linux kernel with AMD display support
2. Manipulate display configuration to invoke amdgpu_dm with a null stream
3. Trigger dc_is_stream_unchanged without null guard
4. Induce kernel panic via null dereference

How to detect it

Review kernel panic and oops logs for references to amdgpu_dm, dc_is_stream_unchanged, or forward null dereference patterns in the display driver; correlate with display configuration changes.

What your security team should do

• Prioritize kernel upgrades to the fixed commit on all AMD GPU hosts
• Test display-related workloads post-update to confirm stability
• Monitor kernel logs for amdgpu_dm related panics until patched