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

> A NULL pointer dereference in the Linux kernel's AMD display driver can cause a system crash during hardware initialization.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 May 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-43337, DEBIAN-CVE-2026-43337, GHSA-5cr7-8523-mgr2, ROOT-OS-DEBIAN-13-CVE-2026-43337, UBUNTU-CVE-2026-43337

## What is CVE-2026-43337?

CVE-2026-43337 is a medium-severity vulnerability in Linux kernel, published on 8 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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)

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-43337?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43337?

Apply the vendor's patch.

## Is CVE-2026-43337 being exploited?

There is no known exploitation of CVE-2026-43337 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43337 and fix it if it is affected.

What it is: CVE-2026-43337 is a medium-severity vulnerability in Linux kernel, published on 8 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-43337 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-43337/ (Markdown: https://insights.sbomify.com/CVE-2026-43337/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43337
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43337
- OSV: https://osv.dev/vulnerability/CVE-2026-43337

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43337/
Summaries are generated and may contain mistakes; the official description above is the record.