Bug 2468117 (CVE-2026-43337)

Summary: CVE-2026-43337 kernel: drm/amd/display: Fix NULL pointer dereference in dcn401_init_hw()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's `drm/amd/display` component. This flaw occurs because the `dcn401_init_hw()` function does not properly validate a callback pointer (`update_bw_bounding_box`) before use. This can lead to a NULL pointer dereference, potentially causing a system crash or denial of service.
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Description OSIDB Bzimport 2026-05-08 14:05:21 UTC 
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)
Comment 1 Alexander B 2026-05-15 11:00:47 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-43337.mbox