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7.8
CVE-2025-38552: Linux Kernel: MPTCP Subflow Creation Can Be Interrupted
CVE-2025-38552
Summary
A fix has been made to prevent a situation where a subflow in the Linux kernel's MPTCP (Multipath TCP) feature can be interrupted while being created, potentially causing issues. This has been addressed by introducing a new flag to manage socket state and protect against additional subflow creation. If you're using MPTCP, ensure you update your Linux kernel to the latest version to maintain secure operation.
What to do
No fix is available yet. Check with your software vendor for updates.
Affected software
| Vendor | Product | Affected versions |
|---|---|---|
| linux | linux_kernel |
>= 5.15, < 6.1.149 >= 6.2, < 6.6.101 >= 6.7, < 6.12.40 >= 6.13, < 6.15.8 6.16 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| debian | debian_linux |
11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* |
Original title
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 be...
Original 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.
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.
nvd CVSS3.1
7.8
- https://git.kernel.org/stable/c/659da22dee5ff316ba63bdaeeac7b58b5442f6c2 Patch
- https://git.kernel.org/stable/c/7c96d519ee15a130842a6513530b4d20acd2bfcd Patch
- https://git.kernel.org/stable/c/c476d627584b7589a134a8b48dd5c6639e4401c5 Patch
- https://git.kernel.org/stable/c/def5b7b2643ebba696fc60ddf675dca13f073486 Patch
- https://git.kernel.org/stable/c/f81b6fbe13c7fc413b5158cdffc6a59391a2a8db Patch
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html Third Party Advisory Mailing List
Published: 16 Aug 2025 · Updated: 17 Jul 2026 · First seen: 7 Mar 2026