# CVE-2023-53990: SMB3: Add missing locks to protect deferred close file list

> A race condition in the Linux kernel SMB3 implementation can lead to a denial of service due to missing locks on the deferred close file list.

- **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:** 24 Dec 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-53990, DEBIAN-CVE-2023-53990, GHSA-8hvc-93qx-9q29, UBUNTU-CVE-2023-53990

## What is CVE-2023-53990?

CVE-2023-53990 is a high-severity vulnerability in Linux, published on 24 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:

SMB3: Add missing locks to protect deferred close file list

cifs_del_deferred_close function has a critical section which modifies
the deferred close file list. We must acquire deferred_lock before
calling cifs_del_deferred_close function.

## Which versions are affected by CVE-2023-53990?


## How do I fix CVE-2023-53990?

Apply the vendor's patch.

## Is CVE-2023-53990 being exploited?

There is no known exploitation of CVE-2023-53990 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-53990 and fix it if it is affected.

What it is: CVE-2023-53990 is a high-severity vulnerability in Linux, published on 24 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-2023-53990 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-2023-53990/ (Markdown: https://insights.sbomify.com/CVE-2023-53990/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53990
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53990
- OSV: https://osv.dev/vulnerability/CVE-2023-53990

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53990/
Summaries are generated and may contain mistakes; the official description above is the record.