# CVE-2026-93827: virtio-fs: avoid double-free on failed queue setup

> A double-free vulnerability in the Linux kernel's virtio-fs driver allows attackers to cause a denial of service or potentially execute code during device probe failure.

- **Severity:** High 8.4 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 24 Sep 2026
- **Updated:** 25 Sep 2026
- **Also known as:** AZL-103925, BELL-CVE-2026-93827, DEBIAN-CVE-2026-93827, GHSA-898x-h72w-ghmm, UBUNTU-CVE-2026-93827

## What is CVE-2026-93827?

CVE-2026-93827 is a high-severity memory corruption vulnerability in Linux, published on 24 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-fs: avoid double-free on failed queue setup

virtio_fs_setup_vqs() allocates fs->vqs and fs->mq_map before calling
virtio_find_vqs(). If virtio_find_vqs() fails, the error path frees both
pointers and returns an error to virtio_fs_probe().

virtio_fs_probe() then drops the last kobject reference, and
virtio_fs_ktype_release() frees fs->vqs and fs->mq_map again. This leaves
dangling pointers in struct virtio_fs and can trigger a double-free during
probe failure cleanup.

Set fs->vqs and fs->mq_map to NULL immediately after kfree() in the
virtio_fs_setup_vqs() error path so that the later kobject release sees an
uninitialized state and kfree(NULL) becomes harmless.

This can be reproduced when a broken virtio-fs device advertises more
request queues than the transport actually provides. In that case
virtio_find_vqs() fails while setting up the extra queue, and the probe
path reaches the double-free cleanup sequence.

## Which versions are affected by CVE-2026-93827?


## How do I fix CVE-2026-93827?

Apply the vendor's patch.

## Is CVE-2026-93827 being exploited?

There is no known exploitation of CVE-2026-93827 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93827 and fix it if it is affected.

What it is: CVE-2026-93827 is a high-severity memory corruption vulnerability in Linux, published on 24 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-2026-93827 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-2026-93827/ (Markdown: https://insights.sbomify.com/CVE-2026-93827/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93827
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93827
- OSV: https://osv.dev/vulnerability/CVE-2026-93827

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93827/
Summaries are generated and may contain mistakes; the official description above is the record.