# CVE-2026-89445: iommufd: Fix UAF in selftest IOPF reporting

> A use-after-free in the Linux kernel iommufd selftest allows attackers to potentially execute code or escalate privileges via race conditions.

- **Severity:** High 8.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-89445, DEBIAN-CVE-2026-89445, GHSA-52p7-c9pg-r5j6, UBUNTU-CVE-2026-89445

## What is CVE-2026-89445?

CVE-2026-89445 is a high-severity use after free 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: Fix UAF in selftest IOPF reporting

IOMMUFD selftest TRIGGER_IOPF borrows an attach handle from
group->pasid_array without synchronizing against PASID detach,
then a concurrent iommu_report_device_fault() can dereference
that borrowed handle's domain pointer after the detach erases
the handle and frees the backing struct iommufd_attach_handle.
TRIGGER_IOPF then dereferences the freed handle, causing a UAF.

Fix by adding a iopf_rwsem in mock_dev to follow the expected design
of a real driver. Hold its read side across the whole
iommu_report_device_fault() call, and its write side around every
path that attaches, detaches, or replaces a device domain.
This can block new reports and drains in-flight reports before an old
attach handle or the IOPF fault parameter can be removed.
Also take the write side while registering a mock device, since
it can invoke the mock driver's default-domain attach callback.

## Which versions are affected by CVE-2026-89445?


## How do I fix CVE-2026-89445?

Apply the vendor's patch.

## Is CVE-2026-89445 being exploited?

There is no known exploitation of CVE-2026-89445 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89445 and fix it if it is affected.

What it is: CVE-2026-89445 is a high-severity use after free 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-2026-89445 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-2026-89445/ (Markdown: https://insights.sbomify.com/CVE-2026-89445/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89445
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89445
- OSV: https://osv.dev/vulnerability/CVE-2026-89445

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89445/
Summaries are generated and may contain mistakes; the official description above is the record.