# CVE-2026-43236: drm/atmel-hlcdc: fix use-after-free of drm_crtc_commit after release

> A use-after-free in the Atmel HLCDC DRM driver allows attackers to execute arbitrary code or escalate privileges via crafted device interactions.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 6 May 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-43236, DEBIAN-CVE-2026-43236, GHSA-j77r-m2hp-2792, ROOT-OS-DEBIAN-11-CVE-2026-43236, ROOT-OS-UBUNTU-2204-CVE-2026-43236, ROOT-OS-UBUNTU-2404-CVE-2026-43236, UBUNTU-CVE-2026-43236

## What is CVE-2026-43236?

CVE-2026-43236 is a high-severity use after free vulnerability in Linux kernel, published on 6 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/atmel-hlcdc: fix use-after-free of drm_crtc_commit after release

The atmel_hlcdc_plane_atomic_duplicate_state() callback was copying
the atmel_hlcdc_plane state structure without properly duplicating the
drm_plane_state. In particular, state->commit remained set to the old
state commit, which can lead to a use-after-free in the next
drm_atomic_commit() call.

Fix this by calling
__drm_atomic_helper_duplicate_plane_state(), which correctly clones
the base drm_plane_state (including the ->commit pointer).

It has been seen when closing and re-opening the device node while
another DRM client (e.g. fbdev) is still attached:

=============================================================================
BUG kmalloc-64 (Not tainted): Poison overwritten
-----------------------------------------------------------------------------

0xc611b344-0xc611b344 @offset=836. First byte 0x6a instead of 0x6b
FIX kmalloc-64: Restoring Poison 0xc611b344-0xc611b344=0x6b
Allocated in drm_atomic_helper_setup_commit+0x1e8/0x7bc age=178 cpu=0
pid=29
 drm_atomic_helper_setup_commit+0x1e8/0x7bc
 drm_atomic_helper_commit+0x3c/0x15c
 drm_atomic_commit+0xc0/0xf4
 drm_framebuffer_remove+0x4cc/0x5a8
 drm_mode_rmfb_work_fn+0x6c/0x80
 process_one_work+0x12c/0x2cc
 worker_thread+0x2a8/0x400
 kthread+0xc0/0xdc
 ret_from_fork+0x14/0x28
Freed in drm_atomic_helper_commit_hw_done+0x100/0x150 age=8 cpu=0
pid=169
 drm_atomic_helper_commit_hw_done+0x100/0x150
 drm_atomic_helper_commit_tail+0x64/0x8c
 commit_tail+0x168/0x18c
 drm_atomic_helper_commit+0x138/0x15c
 drm_atomic_commit+0xc0/0xf4
 drm_atomic_helper_set_config+0x84/0xb8
 drm_mode_setcrtc+0x32c/0x810
 drm_ioctl+0x20c/0x488
 sys_ioctl+0x14c/0xc20
 ret_fast_syscall+0x0/0x54
Slab 0xef8bc360 objects=21 used=16 fp=0xc611b7c0
flags=0x200(workingset|zone=0)
Object 0xc611b340 @offset=832 fp=0xc611b7c0

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-43236?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43236?

Apply the vendor's patch.

## Is CVE-2026-43236 being exploited?

There is no known exploitation of CVE-2026-43236 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-2026-43236 and fix it if it is affected.

What it is: CVE-2026-43236 is a high-severity use after free vulnerability in Linux kernel, published on 6 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-2026-43236 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-2026-43236/ (Markdown: https://insights.sbomify.com/CVE-2026-43236/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43236
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43236
- OSV: https://osv.dev/vulnerability/CVE-2026-43236

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43236/
Summaries are generated and may contain mistakes; the official description above is the record.