# CVE-2026-89447: iommufd: Avoid locking internal accesses during unmap

> A local attacker can trigger a reference leak in the Linux kernel iommufd subsystem, potentially leading to resource exhaustion and 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:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-89447, DEBIAN-CVE-2026-89447, GHSA-jq6v-47fj-pp2p, UBUNTU-CVE-2026-89447

## What is CVE-2026-89447?

CVE-2026-89447 is a denial of service vulnerability in Linux, published on 11 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:

iommufd: Avoid locking internal accesses during unmap

iommufd_access_notify_unmap() skips internal accesses because they do
not have an external unmap callback to invoke.

However, the current test calls iommufd_lock_obj() before checking
whether the access is internal. If iommufd_lock_obj() succeeds, the loop
then sees the internal access and continues, bypassing the matching
iommufd_put_object() used by the normal unmap path. This leaks the
object reference taken by iommufd_lock_obj().

Check for internal accesses first so skipped entries are never locked.

## Which versions are affected by CVE-2026-89447?


## How do I fix CVE-2026-89447?

Apply the vendor's patch.

## Is CVE-2026-89447 being exploited?

There is no known exploitation of CVE-2026-89447 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89447 and fix it if it is affected.

What it is: CVE-2026-89447 is a denial of service vulnerability in Linux, published on 11 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-2026-89447 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-2026-89447/ (Markdown: https://insights.sbomify.com/CVE-2026-89447/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89447
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89447
- OSV: https://osv.dev/vulnerability/CVE-2026-89447

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89447/
Summaries are generated and may contain mistakes; the official description above is the record.