# CVE-2025-38499: clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns

> A missing capability check in the Linux kernel allows local attackers to escalate privileges by cloning private mounts without proper user namespace authorization.

- **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:** 11 Aug 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-66174, AZL-73470, BELL-CVE-2025-38499, DEBIAN-CVE-2025-38499, GHSA-cc85-5h45-qhc8, RHSA-2025:23730, ROOT-OS-DEBIAN-11-CVE-2025-38499, ROOT-OS-DEBIAN-12-CVE-2025-38499, ROOT-OS-UBUNTU-2204-CVE-2025-38499, ROOT-OS-UBUNTU-2404-CVE-2025-38499, UBUNTU-CVE-2025-38499

## What is CVE-2025-38499?

CVE-2025-38499 is a high-severity vulnerability in Debian Debian Linux, published on 11 Aug 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:

clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns

What we want is to verify there is that clone won't expose something
hidden by a mount we wouldn't be able to undo.  "Wouldn't be able to undo"
may be a result of MNT_LOCKED on a child, but it may also come from
lacking admin rights in the userns of the namespace mount belongs to.

clone_private_mnt() checks the former, but not the latter.

There's a number of rather confusing CAP_SYS_ADMIN checks in various
userns during the mount, especially with the new mount API; they serve
different purposes and in case of clone_private_mnt() they usually,
but not always end up covering the missing check mentioned above.

## Which versions are affected by CVE-2025-38499?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `kpatch-patch-5_14_0-611_9_1` | Red Hat:enterprise_linux:9::baseos | All versions | 0:1-1.el9_7 |
| `kpatch-patch-5_14_0-611_9_1-debuginfo` | Red Hat:enterprise_linux:9::baseos | All versions | 0:1-1.el9_7 |
| `kpatch-patch-5_14_0-611_9_1-debugsource` | Red Hat:enterprise_linux:9::baseos | All versions | 0:1-1.el9_7 |

Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38499?

Apply the vendor's patch.

## Is CVE-2025-38499 being exploited?

There is no known exploitation of CVE-2025-38499 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-2025-38499 and fix it if it is affected.

What it is: CVE-2025-38499 is a high-severity vulnerability in Debian Debian Linux, published on 11 Aug 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-2025-38499 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-2025-38499/ (Markdown: https://insights.sbomify.com/CVE-2025-38499/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38499
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38499
- OSV: https://osv.dev/vulnerability/CVE-2025-38499

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38499/
Summaries are generated and may contain mistakes; the official description above is the record.