# CVE-2026-80687: iommufd/viommu: Release the igroup lock on the vdevice_size error path

> A missing lock release in the Linux kernel iommufd driver allows local attackers to cause a deadlock 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:** 28 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** BELL-CVE-2026-80687, DEBIAN-CVE-2026-80687, GHSA-fh38-x9qp-g22j, UBUNTU-CVE-2026-80687

## What is CVE-2026-80687?

CVE-2026-80687 is a denial of service vulnerability in Linux, published on 28 Aug 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/viommu: Release the igroup lock on the vdevice_size error path

iommufd_vdevice_alloc_ioctl() takes idev->igroup->lock, then validates the
driver's vdevice_size against the core structure size with a WARN_ON_ONCE.
On failure that guard jumps to out_put_idev, below out_unlock_igroup, so it
skips the mutex_unlock(), leaving the igroup lock held and deadlocking the
next vDEVICE operation on that group.

Jump to out_unlock_igroup instead.

## Which versions are affected by CVE-2026-80687?


## How do I fix CVE-2026-80687?

Apply the vendor's patch.

## Is CVE-2026-80687 being exploited?

There is no known exploitation of CVE-2026-80687 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80687 and fix it if it is affected.

What it is: CVE-2026-80687 is a denial of service vulnerability in Linux, published on 28 Aug 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-2026-80687 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-2026-80687/ (Markdown: https://insights.sbomify.com/CVE-2026-80687/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80687
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80687
- OSV: https://osv.dev/vulnerability/CVE-2026-80687

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80687/
Summaries are generated and may contain mistakes; the official description above is the record.