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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-08 · updated 2026-10-21
Weakness: CWE-476

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)

Affected products

Linux kernel: from 6.11.3 before 6.18.22; from 6.19 before 6.19.12; 6.12, 7.0-rc1, 7.0-rc2, 7.0-rc3, 7.0-rc4, 7.0-rc5 (+1) — fixed in 6.18.22, 6.19.12

How to fix

Upgrade to a fixed version: Linux kernel 6.18.22, 6.19.12. Check the vendor advisory for mitigations.

References

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