CVE-2025-38491Network attack vector

Data corruption and crash via MPTCP fallback race

Published Jul 28, 2025 · Updated Aug 5, 2026

Improper locking in the MPTCP subsystem of Linux and SIMATIC CN 4100 before V5.0 allows remote attackers to corrupt data or crash systems. Fallback eligibility and fallback status are checked and changed separately, so concurrent MPTCP paths can accept payload that failed DSS validation or reset a subflow. Reachability requires an MPTCP-enabled listener or a connection to an attacker-controlled MPTCP peer; no application credentials are required.

CVSS severity8.2
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in the MPTCP subsystem of Linux and SIMATIC CN 4100 before V5.0 allows remote attackers to corrupt data or crash systems. Fallback eligibility and fallback status are checked and changed separately, so concurrent MPTCP paths can accept payload that failed DSS validation or reset a subflow. Reachability requires an MPTCP-enabled listener or a connection to an attacker-controlled MPTCP peer; no application credentials are required.

The record

CVE
CVE-2025-38491
Published
Jul 28, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-667, T1499.004
Attack vector
network
Privileges
unauthenticated

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

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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=0530020a7c8f2204e784f0dbdc882bbd961fdbde <1d82a8fe6ee4afdc92f4e8808c9dad2a6095bbc5
  2. Affected versionversion=0530020a7c8f2204e784f0dbdc882bbd961fdbde <54999dea879fecb761225e28f274b40662918c30
  3. Affected versionversion=0530020a7c8f2204e784f0dbdc882bbd961fdbde <5586518bec27666c747cd52aabb62d485686d0bf
  4. Affected versionversion=0530020a7c8f2204e784f0dbdc882bbd961fdbde <75a4c9ab8a7af0d76b31ccd1188ed178c38b35d2
  5. Affected versionversion=0530020a7c8f2204e784f0dbdc882bbd961fdbde <f8a1d9b18c5efc76784f5a326e905f641f839894
  6. Affected versionversion=5.10.228 <5.11
  7. Affected versionversion=5.15.169 <5.16
  8. Affected versionversion=5.19
  9. Affected versionversion=609937aa962a62e93acfc04dd370b665e6152dfb
  10. Affected versionversion=6654efe264b014d8ea9fc38f79efb568b1b79069

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0530020a7c8f2204e784f0dbdc882bbd961fdbde <1d82a8fe6ee4afdc92f4e8808c9dad2a6095bbc5; version=0530020a7c8f2204e784f0dbdc882bbd961fdbde <54999dea879fecb761225e28f274b40662918c30; version=0530020a7c8f2204e784f0dbdc882bbd961fdbde <5586518bec27666c747cd52aabb62d485686d0bf; version=0530020a7c8f2204e784f0dbdc882bbd961fdbde <75a4c9ab8a7af0d76b31ccd1188ed178c38b35d2; version=0530020a7c8f2204e784f0dbdc882bbd961fdbde <f8a1d9b18c5efc76784f5a326e905f641f839894; version=5.10.228 <5.11; version=5.15.169 <5.16; version=5.19; version=609937aa962a62e93acfc04dd370b665e6152dfb; version=6654efe264b014d8ea9fc38f79efb568b1b79069
Siemens · SIMATIC CN 4100version=0 <V5.0

Published CVSS scores

5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
8.2Linux Kernel CVE TeamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-667Improper Locking
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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