# CVE-2026-68233: drm/vc4: Shut down BO cache timer before teardown

> A race condition in the Linux kernel's VC4 DRM driver allows a local attacker to cause a denial of service by triggering a use-after-free during teardown.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-95135, BELL-CVE-2026-68233, DEBIAN-CVE-2026-68233, GHSA-q3jj-fvxw-r3cf, UBUNTU-CVE-2026-68233

## What is CVE-2026-68233?

CVE-2026-68233 is a vulnerability in Linux, published on 10 Aug 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/vc4: Shut down BO cache timer before teardown

The BO cache timer callback schedules time_work, and time_work can rearm
the timer through vc4_bo_cache_free_old().

vc4_bo_cache_destroy() deletes the timer and then cancels the work, which
does not break that cycle: the work being cancelled can rearm the timer,
and the timer then queues work again after teardown.

Use timer_shutdown_sync() instead, so the timer cannot be rearmed and the
cycle ends with cancel_work_sync().

## Which versions are affected by CVE-2026-68233?


## How do I fix CVE-2026-68233?

Apply the vendor's patch.

## Is CVE-2026-68233 being exploited?

There is no known exploitation of CVE-2026-68233 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68233 and fix it if it is affected.

What it is: CVE-2026-68233 is a vulnerability in Linux, published on 10 Aug 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-2026-68233 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-2026-68233/ (Markdown: https://insights.sbomify.com/CVE-2026-68233/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68233
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68233
- OSV: https://osv.dev/vulnerability/CVE-2026-68233

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68233/
Summaries are generated and may contain mistakes; the official description above is the record.