CVE-2025-38499

Mount isolation bypass via wrong-user-namespace capability check

Published Aug 11, 2025 · Updated Aug 5, 2026

Improper authorization in Linux mount namespaces allows local users to expose mounts hidden by namespace restrictions across affected kernels. The clone_private_mnt function rejects MNT_LOCKED children but fails to verify CAP_SYS_ADMIN in the user namespace governing the source mount. Local low-privileged access is required, and successful use exposes resources hidden by a mount that the caller lacks authority to undo.

CVSS severity5.5
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in Linux mount namespaces allows local users to expose mounts hidden by namespace restrictions across affected kernels. The clone_private_mnt function rejects MNT_LOCKED children but fails to verify CAP_SYS_ADMIN in the user namespace governing the source mount. Local low-privileged access is required, and successful use exposes resources hidden by a mount that the caller lacks authority to undo.

The record

CVE
CVE-2025-38499
Published
Aug 11, 2025
Updated
Aug 5, 2026
Vendor
Siemens
Product
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classifications
T1611
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=V3.1.5 <*

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
The Linux Kernel Organization · Linuxversion=4.14.244 <4.15; version=41812f4b84484530057513478c6770590347dc30; version=4.19.204 <4.20; version=427215d85e8d1476da1a86b8d67aceb485eb3631 <36fecd740de2d542d2091d65d36554ee2bcf9c65; version=427215d85e8d1476da1a86b8d67aceb485eb3631 <38628ae06e2a37770cd794802a3f1310cf9846e3; version=427215d85e8d1476da1a86b8d67aceb485eb3631 <c28f922c9dcee0e4876a2c095939d77fe7e15116; version=427215d85e8d1476da1a86b8d67aceb485eb3631 <d717325b5ecf2a40daca85c61923e17f32306179; version=427215d85e8d1476da1a86b8d67aceb485eb3631 <dc6a664089f10eab0fb36b6e4f705022210191d2; version=427215d85e8d1476da1a86b8d67aceb485eb3631 <e77078e52fbf018ab986efb3c79065ab35025607; version=4.4.281 <4.5; version=4.9.280 <4.10; version=5.10.59 <5.11; version=5.13.11 <5.14; version=5.14; version=517b875dfbf58f0c6c9e32dc90f5cf42d71a42ce; version=5.4.141 <5.5; version=6a002d48a66076524f67098132538bef17e8445e; version=812f39ed5b0b7f34868736de3055c92c7c4cf459; version=963d85d630dabe75a3cfde44a006fec3304d07b8; version=c6e8810d25295acb40a7b69ed3962ff181919571; version=e3eee87c846dc47f6d8eb6d85e7271f24122a279
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=V3.1.5 <*
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1611Escape to Host

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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