# CVE-2026-89823: drm: fix race between partial drm_dev_register() failure and ioctl

> A race condition in the Linux kernel DRM subsystem allows userspace to trigger use-after-free during device registration failure, potentially causing crashes or code execution.

- **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:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101291, BELL-CVE-2026-89823, DEBIAN-CVE-2026-89823, GHSA-hjv8-5wf8-79gw, UBUNTU-CVE-2026-89823

## What is CVE-2026-89823?

CVE-2026-89823 is a high-severity 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:

drm: fix race between partial drm_dev_register() failure and ioctl

If drm_dev_register() fails after registering a minor (e.g. render minor
registered, primary minor fails), userspace could have opened the first
minor and entered a drm_dev_enter() critical section. Since the
unplugged flag was never set, the ioctl proceeds while the error path
tears down device resources.

Fix this by introducing drm_dev_synchronize_unplug(), which sets the
unplugged flag and waits for the SRCU barrier, ensuring all in-flight
drm_dev_enter() critical sections complete before cleanup proceeds; call
it on the error path of drm_dev_register().

## Which versions are affected by CVE-2026-89823?


## How do I fix CVE-2026-89823?

Apply the vendor's patch.

## Is CVE-2026-89823 being exploited?

There is no known exploitation of CVE-2026-89823 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89823 and fix it if it is affected.

What it is: CVE-2026-89823 is a high-severity 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-2026-89823 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-2026-89823/ (Markdown: https://insights.sbomify.com/CVE-2026-89823/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89823
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89823
- OSV: https://osv.dev/vulnerability/CVE-2026-89823

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89823/
Summaries are generated and may contain mistakes; the official description above is the record.