CVE-2025-38552

mptcp: plug races between subflow fail and subflow creation

HIGH
7.8
CVSS Score
Published: August 16, 2025 at 11:34 AM UTC
Updated: October 15, 2026 at 10:18 PM UTC
3 products affected across 3 vendorsLinux KernelDebian LinuxSIMATIC CN 4100

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Severity
HIGH7.8
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: plug races between subflow fail and subflow creation We have races similar to the one addressed by the previous patch between subflow failing and additional subflow creation. They are just harder to trigger. The solution is similar. Use a separate flag to track the condition 'socket state prevent any additional subflow creation' protected by the fallback lock. The socket fallback makes such flag true, and also receiving or sending an MP_FAIL option. The field 'allow_infinite_fallback' is now always touched under the relevant lock, we can drop the ONCE annotation on write.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.15 ≤ v < 6.1.1496.13 ≤ v < 6.15.86.2 ≤ v < 6.6.1016.7 ≤ v < 6.12.40478d770008b03ed9d74bdc8add2315b7fd124ecc6.166.16 rc16.16 rc26.16 rc36.16 rc46.16 rc56.16 rc6
Vendor states this is fixed in 659da22dee5ff316ba63bdaeeac7b58b5442f6c2 (fixed)
Vendor states this is fixed in 7c96d519ee15a130842a6513530b4d20acd2bfcd (fixed)
Vendor states this is fixed in c476d627584b7589a134a8b48dd5c6639e4401c5 (fixed)
Vendor states this is fixed in def5b7b2643ebba696fc60ddf675dca13f073486 (fixed)
Vendor states this is fixed in f81b6fbe13c7fc413b5158cdffc6a59391a2a8db (fixed)
Vendor states this is fixed in 5.15 (unaffected)
Vendor states this is fixed in 6.1.149 (unaffected)
Vendor states this is fixed in 6.12.40 (unaffected)
Vendor states this is fixed in 6.15.8 (unaffected)
Vendor states this is fixed in 6.16 (unaffected)
Vendor states this is fixed in 6.6.101 (unaffected)
v < V5.0
Affected range stops below V5.0, so it looks safe — our inference, not a vendor statement

References (7)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/659da22dee5ff316ba63bdaeeac7b58b5442f6c2
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/7c96d519ee15a130842a6513530b4d20acd2bfcd
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/c476d627584b7589a134a8b48dd5c6639e4401c5
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/def5b7b2643ebba696fc60ddf675dca13f073486
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/f81b6fbe13c7fc413b5158cdffc6a59391a2a8db
Mailing ListThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
Source: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
https://cert-portal.siemens.com/productcert/html/ssa-032379.html

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

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