# CVE-2025-38231: nfsd: Initialize ssc before laundromat_work to prevent NULL dereference

> A race condition in the Linux kernel NFS server can cause a NULL pointer dereference, leading to a denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 4 Jul 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-64722, BELL-CVE-2025-38231, DEBIAN-CVE-2025-38231, GHSA-7q5j-m65f-w95r, ROOT-OS-DEBIAN-11-CVE-2025-38231, ROOT-OS-DEBIAN-12-CVE-2025-38231, ROOT-OS-UBUNTU-2204-CVE-2025-38231, ROOT-OS-UBUNTU-2404-CVE-2025-38231, UBUNTU-CVE-2025-38231

## What is CVE-2025-38231?

CVE-2025-38231 is a medium-severity vulnerability in Debian Debian Linux, published on 4 Jul 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:

nfsd: Initialize ssc before laundromat_work to prevent NULL dereference

In nfs4_state_start_net(), laundromat_work may access nfsd_ssc through
nfs4_laundromat -> nfsd4_ssc_expire_umount. If nfsd_ssc isn't initialized,
this can cause NULL pointer dereference.

Normally the delayed start of laundromat_work allows sufficient time for
nfsd_ssc initialization to complete. However, when the kernel waits too
long for userspace responses (e.g. in nfs4_state_start_net ->
nfsd4_end_grace -> nfsd4_record_grace_done -> nfsd4_cld_grace_done ->
cld_pipe_upcall -> __cld_pipe_upcall -> wait_for_completion path), the
delayed work may start before nfsd_ssc initialization finishes.

Fix this by moving nfsd_ssc initialization before starting laundromat_work.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2025-38231?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38231?

Apply the vendor's patch.

## Is CVE-2025-38231 being exploited?

There is no known exploitation of CVE-2025-38231 in the wild and no public exploit code.

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- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38231 and fix it if it is affected.

What it is: CVE-2025-38231 is a medium-severity vulnerability in Debian Debian Linux, published on 4 Jul 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-2025-38231 in the wild and no public exploit code.

Affected product: Debian Debian 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-2025-38231/ (Markdown: https://insights.sbomify.com/CVE-2025-38231/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38231
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38231
- OSV: https://osv.dev/vulnerability/CVE-2025-38231

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38231/
Summaries are generated and may contain mistakes; the official description above is the record.