CVE-2025-21865

Kernel crash via duplicate GTP device teardown

Published Mar 12, 2025 · Updated Jul 14, 2026

Out-of-bounds write in the Linux kernel GTP driver allows local users to crash affected systems during network namespace teardown. gtp_net_exit_batch_rtnl() can pass the same device to gtp_dellink() twice when its device and UDP socket occupy different namespaces. Triggering the reported kernel BUG requires local low-privilege access, the cross-namespace GTP layout, namespace cleanup, and CONFIG_DEBUG_LIST.

CVSS severity5.5
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in the Linux kernel GTP driver allows local users to crash affected systems during network namespace teardown. gtp_net_exit_batch_rtnl() can pass the same device to gtp_dellink() twice when its device and UDP socket occupy different namespaces. Triggering the reported kernel BUG requires local low-privilege access, the cross-namespace GTP layout, namespace cleanup, and CONFIG_DEBUG_LIST.

The record

CVE
CVE-2025-21865
Published
Mar 12, 2025
Updated
Jul 14, 2026
Vendor
Siemens
Product
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classifications
CWE-787, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 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 <*
Siemens · SIMATIC S7-1500 TM MFP - GNU/Linux subsystemversion=0 <*
The Linux Kernel Organization · Linuxversion=036f8d814a2cd11ee8ef62b8f3e7ce5dec0ee4f3 <cb15bb1bde0ba97cbbed9508e45210dcafec3657; version=5.10.234 <5.10.235; version=5.15.177 <5.15.179; version=5.4.290 <5.4.291; version=5f1678346109ff3a6d229d33437fcba3cce9209d <33eb925c0c26e86ca540a08254806512bf911f22; version=6.1.127 <6.1.130; version=6.12.11 <6.12.17; version=6.13; version=6.6.74 <6.6.80; version=86f73d4ab2f27deeff22ba9336ad103d94f12ac7 <ff81b14010362f6188ca26fec22ff05e4da45595; version=bb11f992f5a475bc68ef959f17a55306f0328495 <9d03e7e37187ae140e716377599493987fb20c5b; version=c986380c1d5274c4d5e935addc807d6791cc23eb <7f86fb07db65a470d0c11f79da551bd9466357dc; version=eb28fd76c0a08a47b470677c6cef9dd1c60e92d1 <37e7644b961600ef0beb01d3970c3034a62913af; version=eb28fd76c0a08a47b470677c6cef9dd1c60e92d1 <4ccacf86491d33d2486b62d4d44864d7101b299d; version=efec287cbac92ac6ee8312a89221854760e13b34 <b70fa591b066d52b141fc430ffdee35b6cc87a66
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

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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

CWE-787Out-of-bounds Write
T1499Endpoint Denial of Service

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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