CVE-2025-38552Network attack vector

Remote stream corruption and crash via MPTCP race

Published Aug 16, 2025 · Updated Aug 5, 2026

Race condition in Linux kernel MPTCP and SIMATIC CN 4100 before V5.0 allows remote attackers to corrupt streams or crash hosts. The fallback and MP_FAIL paths update allow_infinite_fallback without consistently holding fallback_lock, so an MP_JOIN subflow can be created after fallback should forbid it. An unauthenticated MPTCP peer can drive both packet paths; a successful race can desynchronize a connection, expose kernel-log pointers, or panic configured hosts.

CVSS severity9.4
Critical
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux kernel MPTCP and SIMATIC CN 4100 before V5.0 allows remote attackers to corrupt streams or crash hosts. The fallback and MP_FAIL paths update allow_infinite_fallback without consistently holding fallback_lock, so an MP_JOIN subflow can be created after fallback should forbid it. An unauthenticated MPTCP peer can drive both packet paths; a successful race can desynchronize a connection, expose kernel-log pointers, or panic configured hosts.

The record

CVE
CVE-2025-38552
Published
Aug 16, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-20, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 16, 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=478d770008b03ed9d74bdc8add2315b7fd124ecc <659da22dee5ff316ba63bdaeeac7b58b5442f6c2
  2. Affected versionversion=478d770008b03ed9d74bdc8add2315b7fd124ecc <7c96d519ee15a130842a6513530b4d20acd2bfcd
  3. Affected versionversion=478d770008b03ed9d74bdc8add2315b7fd124ecc <c476d627584b7589a134a8b48dd5c6639e4401c5
  4. Affected versionversion=478d770008b03ed9d74bdc8add2315b7fd124ecc <def5b7b2643ebba696fc60ddf675dca13f073486
  5. Affected versionversion=478d770008b03ed9d74bdc8add2315b7fd124ecc <f81b6fbe13c7fc413b5158cdffc6a59391a2a8db
  6. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=478d770008b03ed9d74bdc8add2315b7fd124ecc <659da22dee5ff316ba63bdaeeac7b58b5442f6c2; version=478d770008b03ed9d74bdc8add2315b7fd124ecc <7c96d519ee15a130842a6513530b4d20acd2bfcd; version=478d770008b03ed9d74bdc8add2315b7fd124ecc <c476d627584b7589a134a8b48dd5c6639e4401c5; version=478d770008b03ed9d74bdc8add2315b7fd124ecc <def5b7b2643ebba696fc60ddf675dca13f073486; version=478d770008b03ed9d74bdc8add2315b7fd124ecc <f81b6fbe13c7fc413b5158cdffc6a59391a2a8db; version=5.15
Siemens · SIMATIC CN 4100version=0 <V5.0

Published CVSS scores

5.3Siemens ProductCERTCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H
9.4Linux kernel CVE teamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H
7.8Canonical UbuntuCVSS: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.

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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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
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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