# CVE-2025-39697: NFS: Fix a race when updating an existing write

> A race condition in the Linux kernel's NFS implementation can lead to system instability or denial of service.

- **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:** 5 Sep 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-66926, AZL-73716, BELL-CVE-2025-39697, DEBIAN-CVE-2025-39697, GHSA-3fr6-pgc4-qmrv, ROOT-OS-DEBIAN-11-CVE-2025-39697, ROOT-OS-DEBIAN-12-CVE-2025-39697, ROOT-OS-DEBIAN-13-CVE-2025-39697, ROOT-OS-UBUNTU-2204-CVE-2025-39697, ROOT-OS-UBUNTU-2404-CVE-2025-39697, UBUNTU-CVE-2025-39697

## What is CVE-2025-39697?

CVE-2025-39697 is a high-severity vulnerability in Debian Debian Linux, published on 5 Sep 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:

NFS: Fix a race when updating an existing write

After nfs_lock_and_join_requests() tests for whether the request is
still attached to the mapping, nothing prevents a call to
nfs_inode_remove_request() from succeeding until we actually lock the
page group.
The reason is that whoever called nfs_inode_remove_request() doesn't
necessarily have a lock on the page group head.

So in order to avoid races, let's take the page group lock earlier in
nfs_lock_and_join_requests(), and hold it across the removal of the
request in nfs_inode_remove_request().

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2025-39697?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-39697?

Apply the vendor's patch.

## Is CVE-2025-39697 being exploited?

There is no known exploitation of CVE-2025-39697 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [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-2025-39697 and fix it if it is affected.

What it is: CVE-2025-39697 is a high-severity vulnerability in Debian Debian Linux, published on 5 Sep 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-2025-39697 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-2025-39697/ (Markdown: https://insights.sbomify.com/CVE-2025-39697/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39697
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39697
- OSV: https://osv.dev/vulnerability/CVE-2025-39697

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39697/
Summaries are generated and may contain mistakes; the official description above is the record.