# CVE-2026-23034: drm/amdgpu/userq: Fix fence reference leak on queue teardown v2

> A missing reference count decrement in the AMD GPU driver causes a memory leak and kernel panic during module unload, leading to denial of service.

- **Severity:** Not scored
- **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:** 31 Jan 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-23034, DEBIAN-CVE-2026-23034, GHSA-hv59-hh7h-7h9r, UBUNTU-CVE-2026-23034

## What is CVE-2026-23034?

CVE-2026-23034 is a memory corruption vulnerability in Linux, published on 31 Jan 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/amdgpu/userq: Fix fence reference leak on queue teardown v2

The user mode queue keeps a pointer to the most recent fence in
userq->last_fence. This pointer holds an extra dma_fence reference.

When the queue is destroyed, we free the fence driver and its xarray,
but we forgot to drop the last_fence reference.

Because of the missing dma_fence_put(), the last fence object can stay
alive when the driver unloads. This leaves an allocated object in the
amdgpu_userq_fence slab cache and triggers

This is visible during driver unload as:

  BUG amdgpu_userq_fence: Objects remaining on __kmem_cache_shutdown()
  kmem_cache_destroy amdgpu_userq_fence: Slab cache still has objects
  Call Trace:
    kmem_cache_destroy
    amdgpu_userq_fence_slab_fini
    amdgpu_exit
    __do_sys_delete_module

Fix this by putting userq->last_fence and clearing the pointer during
amdgpu_userq_fence_driver_free().

This makes sure the fence reference is released and the slab cache is
empty when the module exits.

v2: Update to only release userq->last_fence with dma_fence_put()
    (Christian)

(cherry picked from commit 8e051e38a8d45caf6a866d4ff842105b577953bb)

## Which versions are affected by CVE-2026-23034?


## How do I fix CVE-2026-23034?

Apply the vendor's patch.

## Is CVE-2026-23034 being exploited?

There is no known exploitation of CVE-2026-23034 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23034 and fix it if it is affected.

What it is: CVE-2026-23034 is a memory corruption vulnerability in Linux, published on 31 Jan 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-2026-23034 in the wild and no public exploit code.

Affected product: 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-2026-23034/ (Markdown: https://insights.sbomify.com/CVE-2026-23034/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23034
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23034
- OSV: https://osv.dev/vulnerability/CVE-2026-23034

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23034/
Summaries are generated and may contain mistakes; the official description above is the record.