CVE-2025-38470

Local kernel compromise via VLAN 0 refcount imbalance

Published Jul 28, 2025 · Updated Aug 5, 2026

A VLAN refcount flaw in the Linux kernel allows local users to corrupt kernel memory through network-namespace configuration. The 8021q event handler removes VLAN 0 according to the current rx-vlan-filter setting instead of tracking whether it added that entry, causing a leak or premature free. A low-privileged user with namespace-relative CAP_NET_ADMIN can drive the deterministic transition, leading to heap disclosure, control-flow hijacking, a crash, or a persistent networking hang.

CVSS severity7.8
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A VLAN refcount flaw in the Linux kernel allows local users to corrupt kernel memory through network-namespace configuration. The 8021q event handler removes VLAN 0 according to the current rx-vlan-filter setting instead of tracking whether it added that entry, causing a leak or premature free. A low-privileged user with namespace-relative CAP_NET_ADMIN can drive the deterministic transition, leading to heap disclosure, control-flow hijacking, a crash, or a persistent networking hang.

The record

CVE
CVE-2025-38470
Published
Jul 28, 2025
Updated
Aug 5, 2026
Vendor
Siemens
Product
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classifications
CWE-20, T1068, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 28, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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=2.6.36; version=ad1afb00393915a51c21b1ae8704562bf036855f <047b61a24d7c866c502aeeea482892969a68f216; version=ad1afb00393915a51c21b1ae8704562bf036855f <35142b3816832889e50164d993018ea5810955ae; version=ad1afb00393915a51c21b1ae8704562bf036855f <579d4f9ca9a9a605184a9b162355f6ba131f678d; version=ad1afb00393915a51c21b1ae8704562bf036855f <8984bcbd1edf5bee5be06ad771d157333b790c33; version=ad1afb00393915a51c21b1ae8704562bf036855f <93715aa2d80e6c5cea1bb486321fc4585076928b; version=ad1afb00393915a51c21b1ae8704562bf036855f <ba48d3993af23753e1f1f01c8d592de9c7785f24; version=ad1afb00393915a51c21b1ae8704562bf036855f <bb515c41306454937464da055609b5fb0a27821b; version=ad1afb00393915a51c21b1ae8704562bf036855f <d43ef15bf4856c8c4c6c3572922331a5f06deb77
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

7.8Linux Kernel CNACVSS: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
6.8SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5SUSECVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1068Exploitation for Privilege Escalation
T1499.004Application or System Exploitation

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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