# CVE-2026-89800: drm/nouveau/uvmm: clear the dirty flag when unwinding an OP_UNMAP_SPARSE

> A flaw in the Linux kernel nouveau driver allows local attackers to cause permanent denial of service by triggering a specific GPU memory unmap failure.

- **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:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101622, BELL-CVE-2026-89800, DEBIAN-CVE-2026-89800, GHSA-g7qr-ggg3-47g8, UBUNTU-CVE-2026-89800

## What is CVE-2026-89800?

CVE-2026-89800 is a denial of service 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/nouveau/uvmm: clear the dirty flag when unwinding an OP_UNMAP_SPARSE

A successful OP_UNMAP_SPARSE marks its region dirty with
nouveau_uvma_region_dirty() and defers the teardown to
nouveau_uvmm_bind_job_cleanup(); it does not remove the region from
uvmm->region_mt.

If a later op in the job fails, the unwind path never clears reg->dirty
(set in one place, cleared nowhere) and sets op->reg = NULL, so cleanup
skips the teardown. The region is left in the tree with dirty set and its
completion never signalled. Later binds over that range then fail
permanently -- -ENOENT or -EINVAL from the dirty checks, or an unkillable
wait_for_completion() in bind_validate_region() -- for the lifetime of
the uvmm.

Clear reg->dirty when the unwind reverts the sparse unmap, restoring the
region to the state it was found in.

## Which versions are affected by CVE-2026-89800?


## How do I fix CVE-2026-89800?

Apply the vendor's patch.

## Is CVE-2026-89800 being exploited?

There is no known exploitation of CVE-2026-89800 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89800 and fix it if it is affected.

What it is: CVE-2026-89800 is a denial of service 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-2026-89800 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-2026-89800/ (Markdown: https://insights.sbomify.com/CVE-2026-89800/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89800
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89800
- OSV: https://osv.dev/vulnerability/CVE-2026-89800

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89800/
Summaries are generated and may contain mistakes; the official description above is the record.