# CVE-2026-53381: virtiofs: fix UAF on submount umount

> A use-after-free vulnerability in the Linux kernel's virtiofs submount umount process can cause a system crash or potentially allow code execution.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 19 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-53381, DEBIAN-CVE-2026-53381, GHSA-525m-f6h4-6w58, ROOT-OS-DEBIAN-11-CVE-2026-53381, ROOT-OS-UBUNTU-2204-CVE-2026-53381, UBUNTU-CVE-2026-53381

## What is CVE-2026-53381?

CVE-2026-53381 is a high-severity use after free vulnerability in Linux kernel, published on 19 Jul 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:

virtiofs: fix UAF on submount umount

iput() called from fuse_release_end() can Oops if the super block has
already been destroyed.  Normally this is prevented by waiting for
num_waiting to go down to zero before commencing with super block shutdown.

This only works, however, for the last submount instance, as the wait
counter is per connection, not per superblock.

Revert to using synchronous release requests for the auto_submounts case,
which is virtiofs only at this time.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-53381?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53381?

Apply the vendor's patch.

## Is CVE-2026-53381 being exploited?

There is no known exploitation of CVE-2026-53381 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53381 and fix it if it is affected.

What it is: CVE-2026-53381 is a high-severity use after free vulnerability in Linux kernel, published on 19 Jul 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-2026-53381 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-53381/ (Markdown: https://insights.sbomify.com/CVE-2026-53381/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53381
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53381
- OSV: https://osv.dev/vulnerability/CVE-2026-53381

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53381/
Summaries are generated and may contain mistakes; the official description above is the record.