# CVE-2025-68242: NFS: Fix LTP test failures when timestamps are delegated

> A missing UID check in Linux kernel NFS allows low-privileged users to modify file timestamps on delegated inodes, potentially leading to privilege escalation or data integrity issues.

- **Severity:** Not scored
- **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:** 16 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-68242, DEBIAN-CVE-2025-68242, GHSA-x3jc-4xg9-3pr6, ROOT-OS-DEBIAN-13-CVE-2025-68242, UBUNTU-CVE-2025-68242

## What is CVE-2025-68242?

CVE-2025-68242 is a missing authorization vulnerability in Linux, published on 16 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:

NFS: Fix LTP test failures when timestamps are delegated

The utimes01 and utime06 tests fail when delegated timestamps are
enabled, specifically in subtests that modify the atime and mtime
fields using the 'nobody' user ID.

The problem can be reproduced as follow:

# echo "/media *(rw,no_root_squash,sync)" >> /etc/exports
# export -ra
# mount -o rw,nfsvers=4.2 127.0.0.1:/media /tmpdir
# cd /opt/ltp
# ./runltp -d /tmpdir -s utimes01
# ./runltp -d /tmpdir -s utime06

This issue occurs because nfs_setattr does not verify the inode's
UID against the caller's fsuid when delegated timestamps are
permitted for the inode.

This patch adds the UID check and if it does not match then the
request is sent to the server for permission checking.

## Which versions are affected by CVE-2025-68242?


## How do I fix CVE-2025-68242?

Apply the vendor's patch.

## Is CVE-2025-68242 being exploited?

There is no known exploitation of CVE-2025-68242 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68242 and fix it if it is affected.

What it is: CVE-2025-68242 is a missing authorization vulnerability in Linux, published on 16 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-2025-68242 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-2025-68242/ (Markdown: https://insights.sbomify.com/CVE-2025-68242/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68242
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68242
- OSV: https://osv.dev/vulnerability/CVE-2025-68242

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68242/
Summaries are generated and may contain mistakes; the official description above is the record.