# CVE-2026-90129: virtio_balloon: quiesce balloon work before device shutdown

> A missing shutdown handler in the Linux kernel virtio_balloon driver causes a fatal panic during reboot if panic_on_warn is enabled.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-90129, DEBIAN-CVE-2026-90129, GHSA-mrw4-8pgr-v6w5, UBUNTU-CVE-2026-90129

## What is CVE-2026-90129?

CVE-2026-90129 is a denial of service vulnerability in Linux, published on 17 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:

virtio_balloon: quiesce balloon work before device shutdown

Commit 8bd2fa086a04 ("virtio: break and reset virtio devices on
device_shutdown()") added a generic virtio bus .shutdown handler that
breaks and resets every virtio device during device_shutdown(), i.e. on
reboot and kexec.

virtio_balloon provides no .shutdown of its own, so that generic path
runs while the balloon's asynchronous work is still armed. Once the
device has been broken, virtqueue_add_inbuf() in
virtballoon_free_page_report() returns -EIO and trips its
WARN_ON_ONCE(). On a kernel booted with panic_on_warn that turns an
ordinary reboot, for example a kexec based upgrade, into a fatal panic
in the middle of device_shutdown(), so the machine never reaches the
new kernel.

Relaxing that single WARN_ON_ONCE() would only hide the symptom: the
inflate/deflate and OOM paths do not warn, they call
wait_event(vb->acked, ...) and would instead block forever on a broken
queue that can no longer complete. The device has to be quiesced, not
just kept quiet.

Add a .shutdown handler that quiesces the balloon via the shared
virtballoon_quiesce() helper while the device is still alive, and only
then breaks and resets it via virtio_device_shutdown(). Unlike
virtballoon_remove() the balloon workqueue is not destroyed, as shutdown
does not free the device and cancel_work_sync() together with stop_update
already prevent any further work from being queued.

## Which versions are affected by CVE-2026-90129?


## How do I fix CVE-2026-90129?

Apply the vendor's patch.

## Is CVE-2026-90129 being exploited?

There is no known exploitation of CVE-2026-90129 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90129 and fix it if it is affected.

What it is: CVE-2026-90129 is a denial of service vulnerability in Linux, published on 17 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-2026-90129 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-2026-90129/ (Markdown: https://insights.sbomify.com/CVE-2026-90129/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90129
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90129
- OSV: https://osv.dev/vulnerability/CVE-2026-90129

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90129/
Summaries are generated and may contain mistakes; the official description above is the record.