CVE-2026-43337: drm/amd/display: Fix NULL pointer dereference in dcn401_init_hw()

Vulnerability summary

CVE-2026-43337 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.11% chance of exploitation in the next 30 days, higher than 1.4% of scored vulnerabilities.

Timeline

1. 08-05-2026
   PublishedVulnerability first disclosed.
2. 21-10-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix NULL pointer dereference in dcn401_init_hw() dcn401_init_hw() assumes that update_bw_bounding_box() is valid when entering the update path. However, the existing condition: ((!fams2_enable && update_bw_bounding_box) || freq_changed) does not guarantee this, as the freq_changed branch can evaluate to true independently of the callback pointer. This can result in calling update_bw_bounding_box() when it is NULL. Fix this by separating the update condition from the pointer checks and ensuring the callback, dc->clk_mgr, and bw_params are validated before use. Fixes the below: ../dc/hwss/dcn401/dcn401_hwseq.c:367 dcn401_init_hw() error: we previously assumed 'dc->res_pool->funcs->update_bw_bounding_box' could be null (see line 362) (cherry picked from commit 86117c5ab42f21562fedb0a64bffea3ee5fcd477)

• CWE-476NULL Pointer DereferenceThe product dereferences a pointer that it expects to be valid but is NULL.