# CVE-2026-89874: media: v4l2-async: avoid deleting unlinked ASC entry on link error

> A null pointer dereference in the Linux kernel's V4L2 async subsystem can cause a system crash when ancillary link creation fails.

- **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:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101628, BELL-CVE-2026-89874, DEBIAN-CVE-2026-89874, GHSA-rmqv-gxqc-vfx4, UBUNTU-CVE-2026-89874

## What is CVE-2026-89874?

CVE-2026-89874 is a vulnerability in Linux, published on 16 Sep 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:

media: v4l2-async: avoid deleting unlinked ASC entry on link error

v4l2_async_match_notify() creates ancillary media links before adding
asc->asc_subdev_entry to sd->asc_list.

If ancillary link creation fails, the function jumps to
err_call_unbind while asc_subdev_entry has not been linked yet. Async
connections are zero-allocated, so the list entry still has NULL next
and prev pointers on this path. Calling list_del() on it can therefore
dereference NULL instead of returning the original link creation error.

Do not delete asc_subdev_entry from err_call_unbind. There is no list
insertion to undo on this path; the bound callback and sub-device
registration are the operations that need to be rolled back.

## Which versions are affected by CVE-2026-89874?


## How do I fix CVE-2026-89874?

Apply the vendor's patch.

## Is CVE-2026-89874 being exploited?

There is no known exploitation of CVE-2026-89874 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89874 and fix it if it is affected.

What it is: CVE-2026-89874 is a vulnerability in Linux, published on 16 Sep 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-2026-89874 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-2026-89874/ (Markdown: https://insights.sbomify.com/CVE-2026-89874/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89874
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89874
- OSV: https://osv.dev/vulnerability/CVE-2026-89874

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89874/
Summaries are generated and may contain mistakes; the official description above is the record.