CVE-2024-26662

What it actually does

Null pointer dereference in dcn21_set_backlight_level() when panel_cntl is null, leading to invalid memory access in the AMD display driver.

Why it matters to the business

Potential kernel crashes or system instability on Linux systems with certain AMD GPUs, resulting in downtime and reduced reliability for display operations.

How an attack unfolds

An attacker with local access triggers the backlight level setting path in the display hardware sequencing code under conditions where the panel control structure has not been initialized, causing the dereference.

How to fix it

Upgrade the Linux kernel to include commit 2e150ccea13129eb048679114808eb9770443e4d or later in the stable tree.

How to confirm the fix worked

Verify the presence of the fixing commit in the kernel source or confirm absence of the static analysis warning for null panel_cntl in dcn21_set_backlight_level().

Typical attack path

1. Obtain local user access on an affected Linux system
2. Configure or trigger display backlight changes via AMD DCN21 hardware
3. Reach the null panel_cntl assumption in dcn21_hwseq.c
4. Trigger kernel panic or memory fault

How to detect it

Review kernel logs for oops or panic entries referencing dcn21_set_backlight_level or dcn21_hwseq.c line 269.

What your security team should do

• Apply the referenced kernel commit to all affected systems
• Reboot systems after patching and monitor for display-related kernel faults
• Prioritize updates on systems with AMD DCN21 hardware