# CVE-2024-26874: drm/mediatek: Fix a null pointer crash in mtk_drm_crtc_finish_page_flip

> A race condition in the Mediatek DRM driver causes a null pointer dereference, leading to a kernel crash and denial of service.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:L/AC:H/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:** 17 Apr 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2024-26874, DEBIAN-CVE-2024-26874, GHSA-q342-fw2j-5cj8, UBUNTU-CVE-2024-26874

## What is CVE-2024-26874?

CVE-2024-26874 is a medium-severity vulnerability in Debian Debian Linux, published on 17 Apr 2024. 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/mediatek: Fix a null pointer crash in mtk_drm_crtc_finish_page_flip

It's possible that mtk_crtc->event is NULL in
mtk_drm_crtc_finish_page_flip().

pending_needs_vblank value is set by mtk_crtc->event, but in
mtk_drm_crtc_atomic_flush(), it's is not guarded by the same
lock in mtk_drm_finish_page_flip(), thus a race condition happens.

Consider the following case:

CPU1                              CPU2
step 1:
mtk_drm_crtc_atomic_begin()
mtk_crtc->event is not null,
                                  step 1:
                                  mtk_drm_crtc_atomic_flush:
                                  mtk_drm_crtc_update_config(
                                      !!mtk_crtc->event)
step 2:
mtk_crtc_ddp_irq ->
mtk_drm_finish_page_flip:
lock
mtk_crtc->event set to null,
pending_needs_vblank set to false
unlock
                                  pending_needs_vblank set to true,

                                  step 2:
                                  mtk_crtc_ddp_irq ->
                                  mtk_drm_finish_page_flip called again,
                                  pending_needs_vblank is still true
                                  //null pointer

Instead of guarding the entire mtk_drm_crtc_atomic_flush(), it's more
efficient to just check if mtk_crtc->event is null before use.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-26874?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2024-26874?

Apply the vendor's patch.

## Is CVE-2024-26874 being exploited?

There is no known exploitation of CVE-2024-26874 in the wild and no public exploit code.

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## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-26874 and fix it if it is affected.

What it is: CVE-2024-26874 is a medium-severity vulnerability in Debian Debian Linux, published on 17 Apr 2024. 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-2024-26874 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2024-26874/ (Markdown: https://insights.sbomify.com/CVE-2024-26874/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-26874
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-26874
- OSV: https://osv.dev/vulnerability/CVE-2024-26874

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-26874/
Summaries are generated and may contain mistakes; the official description above is the record.