Executive brief
A vulnerability in the Linux kernel's AMD display driver could allow a local user to cause a system crash. The issue occurs during the initialization of certain AMD graphics hardware when the system incorrectly handles internal memory pointers. This results in a 'NULL pointer dereference,' which typically leads to a kernel panic or 'Blue Screen' style failure, impacting system availability.
Technical details
A NULL pointer dereference exists in the AMD display driver (DRM) within the dcn401_init_hw() function. The vulnerability is caused by an insufficient conditional check: the code assumed that the update_bw_bounding_box() callback was valid if certain flags were set, but a secondary condition (freq_changed) could trigger the code path even when the callback pointer was NULL. An attacker with local access could potentially trigger this path during hardware initialization or frequency changes, leading to a kernel oops or panic. The fix involves explicitly validating the callback pointer, clk_mgr, and bw_params before invocation.
Affected products
- Linux Linux Kernel DCN401 display driver component
Timeline
- 2026-03-30: patched: Initial patch in main kernel tree
- 2026-05-08: advisory: NVD publication date