CVE-2025-21701

Kernel crash via ethtool unregistration race

Published Feb 13, 2025 · Updated Aug 5, 2026

A race in Linux kernel ethtool netlink operations allows local users to crash the kernel by overlapping requests with device teardown. unregister_netdevice_many_notify can dismantle a device before ethnl_set_channels finishes, causing handlers to lock a destroyed RSS mutex or access freed state. Ordinary local users can control both sides through a user namespace; no user interaction is required, and the ioctl path is unaffected.

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 race in Linux kernel ethtool netlink operations allows local users to crash the kernel by overlapping requests with device teardown. unregister_netdevice_many_notify can dismantle a device before ethnl_set_channels finishes, causing handlers to lock a destroyed RSS mutex or access freed state. Ordinary local users can control both sides through a user namespace; no user interaction is required, and the ioctl path is unaffected.

The record

CVE
CVE-2025-21701
Published
Feb 13, 2025
Updated
Aug 5, 2026
Vendor
Siemens
Product
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classifications
CWE-362, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 13, 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=5.10.87 <5.11; version=5.15.8 <5.15.179; version=5.16; version=7c26da3be1e9843a15b5318f90db8a564479d2ac; version=cfd719f04267108f5f5bf802b9d7de69e99a99f9 <26bc6076798aa4dc83a07d0a386f9e57c94e8517; version=dde91ccfa25fd58f64c397d91b81a4b393100ffa <12e070eb6964b341b41677fd260af5a305316a1f; version=dde91ccfa25fd58f64c397d91b81a4b393100ffa <2f29127e94ae9fdc7497331003d6860e9551cdf3; version=dde91ccfa25fd58f64c397d91b81a4b393100ffa <4dc880245f9b529fa8f476b5553c799d2848b47b; version=dde91ccfa25fd58f64c397d91b81a4b393100ffa <b1cb37a31a482df3dd35a6ac166282dac47664f4; version=dde91ccfa25fd58f64c397d91b81a4b393100ffa <b382ab9b885cbb665e0e70a727f101c981b4edf3
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

7.4CISA-ADPCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
7.4Siemens ProductCERTCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
4.7NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1499.004Endpoint Denial of Service: Application 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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