# CVE-2025-40219: PCI/IOV: Fix race between SR-IOV enable/disable and hotplug

> A race condition in the Linux kernel PCI/IOV subsystem can cause a deadlock when SR-IOV is enabled or disabled during hotplug events, leading to denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Dec 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-71293, BELL-CVE-2025-40219, DEBIAN-CVE-2025-40219, GHSA-p5jg-472w-q92f, ROOT-OS-UBUNTU-2404-CVE-2025-40219, UBUNTU-CVE-2025-40219

## What is CVE-2025-40219?

CVE-2025-40219 is a vulnerability in Linux, published on 4 Dec 2025. 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:

PCI/IOV: Fix race between SR-IOV enable/disable and hotplug

Commit 05703271c3cd ("PCI/IOV: Add PCI rescan-remove locking when
enabling/disabling SR-IOV") tried to fix a race between the VF removal
inside sriov_del_vfs() and concurrent hot unplug by taking the PCI
rescan/remove lock in sriov_del_vfs(). Similarly the PCI rescan/remove lock
was also taken in sriov_add_vfs() to protect addition of VFs.

This approach however causes deadlock on trying to remove PFs with SR-IOV
enabled because PFs disable SR-IOV during removal and this removal happens
under the PCI rescan/remove lock. So the original fix had to be reverted.

Instead of taking the PCI rescan/remove lock in sriov_add_vfs() and
sriov_del_vfs(), fix the race that occurs with SR-IOV enable and disable vs
hotplug higher up in the callchain by taking the lock in
sriov_numvfs_store() before calling into the driver's sriov_configure()
callback.

## Which versions are affected by CVE-2025-40219?


## How do I fix CVE-2025-40219?

Apply the vendor's patch.

## Is CVE-2025-40219 being exploited?

There is no known exploitation of CVE-2025-40219 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40219 and fix it if it is affected.

What it is: CVE-2025-40219 is a vulnerability in Linux, published on 4 Dec 2025. 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-2025-40219 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-2025-40219/ (Markdown: https://insights.sbomify.com/CVE-2025-40219/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40219
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40219
- OSV: https://osv.dev/vulnerability/CVE-2025-40219

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40219/
Summaries are generated and may contain mistakes; the official description above is the record.