CVE-2024-26647

What it actually does

NULL pointer dereference of 'dsc' before the NULL check in link_set_dsc_pps_packet() within the AMD display driver, leading to potential kernel crash or memory corruption on systems with AMD GPUs.

Why it matters to the business

Affected Linux systems using AMD graphics may experience kernel panics requiring reboots and patches, causing downtime; urgency is low given no known exploitation but widespread kernel deployments increase patch scope.

How an attack unfolds

An attacker with local access triggers the DSC packet path in the display driver on AMD hardware to hit the dereference-before-check condition, potentially crashing the kernel or enabling further memory manipulation.

How to fix it

Upgrade to fixed kernel versions including Debian linux 4.13.13-1, Ubuntu linux 3.13.0-137.186, linux-aws 4.4.0-1005.5, linux-azure 4.15.0-1023.24~14.04.1, linux-lts-xenial 4.4.0-103.126~14.04.1, linux 4.4.0-103.126, linux-aws 4.4.0-1043.52, linux-azure 4.11.0-1016.16, linux-euclid 4.4.0-9020.21, linux-gcp 4.13.0-1002.5, linux-hwe 4.10.0-42.46~16.04.1, linux-kvm 4.4.0-1012.17, and linux-oem 4.13.0-1010.11.

How to confirm the fix worked

Verify updated kernel versions match the listed fixed releases and confirm the patch reorders the NULL check before dereferencing dsc in link_set_dsc_pps_packet().

Typical attack path

1. Obtain local user access on an affected Linux system with AMD display hardware
2. Configure or trigger display stream compression (DSC) operations
3. Invoke link_set_dsc_pps_packet() to trigger the early dereference

How to detect it

Review kernel logs for oops or warnings referencing link_set_dsc_pps_packet or display stream compressor dereference errors on AMD hardware.

What your security team should do

• Prioritize kernel updates on all AMD GPU systems within standard maintenance windows
• Monitor for kernel oops involving display link code
• Test display functionality post-upgrade on representative hardware