# CVE-2025-68239: binfmt_misc: restore write access before closing files opened by open_exec()

> A local attacker with high privileges can cause write failures on executable files by triggering an error in binfmt_misc registration, leading to a denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Dec 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-72499, BELL-CVE-2025-68239, DEBIAN-CVE-2025-68239, GHSA-6286-qq46-83p9, ROOT-OS-DEBIAN-11-CVE-2025-68239, ROOT-OS-DEBIAN-12-CVE-2025-68239, ROOT-OS-DEBIAN-13-CVE-2025-68239, ROOT-OS-UBUNTU-2204-CVE-2025-68239, ROOT-OS-UBUNTU-2404-CVE-2025-68239, UBUNTU-CVE-2025-68239

## What is CVE-2025-68239?

CVE-2025-68239 is a 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:

binfmt_misc: restore write access before closing files opened by open_exec()

bm_register_write() opens an executable file using open_exec(), which
internally calls do_open_execat() and denies write access on the file to
avoid modification while it is being executed.

However, when an error occurs, bm_register_write() closes the file using
filp_close() directly. This does not restore the write permission, which
may cause subsequent write operations on the same file to fail.

Fix this by calling exe_file_allow_write_access() before filp_close() to
restore the write permission properly.

## Which versions are affected by CVE-2025-68239?


## How do I fix CVE-2025-68239?

Apply the vendor's patch.

## Is CVE-2025-68239 being exploited?

There is no known exploitation of CVE-2025-68239 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68239 and fix it if it is affected.

What it is: CVE-2025-68239 is a 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-2025-68239 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-2025-68239/ (Markdown: https://insights.sbomify.com/CVE-2025-68239/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68239
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68239
- OSV: https://osv.dev/vulnerability/CVE-2025-68239

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68239/
Summaries are generated and may contain mistakes; the official description above is the record.