High 7.5Published May 1, 2025

CVE-2025-23145mptcp: fix NULL pointer in can_accept_new_subflow

Updated under an hour ago (Oct 27, 2026, 1:00 AM ET)

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No exploitation reported and no EPSS estimate yet.

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In the Linux kernel, the following vulnerability has been resolved: mptcp: fix NULL pointer in can_accept_new_subflow When testing valkey benchmark tool with MPTCP, the kernel panics in 'mptcp_can_accept_new_subflow' because subflow_req->msk is NULL. Call trace: mptcp_can_accept_new_subflow (./net/mptcp/subflow.c:63 (discriminator 4)) (P) subflow_syn_recv_sock (./net/mptcp/subflow.c:854) tcp_check_req (./net/ipv4/tcp_minisocks.c:863) tcp_v4_rcv (./net/ipv4/tcp_ipv4.c:2268) ip_protocol_deliver_rcu (./net/ipv4/ip_input.c:207) ip_local_deliver_finish (./net/ipv4/ip_input.c:234) ip_local_deliver (./net/ipv4/ip_input.c:254) ip_rcv_finish (./net/ipv4/ip_input.c:449) ... According to the debug log, the same req received two SYN-ACK in a very short time, very likely because the client retransmits the syn ack due to multiple reasons. Even if the packets are transmitted with a relevant time interval, they can be processed by the server on different CPUs concurrently). The 'subflow_req->msk' ownership is transferred to the subflow the first, and there will be a risk of a null pointer dereference here. This patch fixes this issue by moving the 'subflow_req->msk' under the `own_req == true` conditional. Note that the !msk check in subflow_hmac_valid() can be dropped, because the same check already exists under the own_req mpj branch where the code has been moved to.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 15, 2026
First seen by InfoSec Signals: Oct 15, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	9466a1ccebbe54ac57fb8a89c2b4b854826546a8 builds before 8cf7fef1bb2ffea7792bcbf71ca00216cecc725d; from 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 before b3088bd2a6790c8efff139d86d7a9d0b1305977b; 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 builds before 855bf0aacd51fced11ea9aa0d5101ee0febaeadb; 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 builds before 7f9ae060ed64aef8f174c5f1ea513825b1be9af1; from 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 before dc81e41a307df523072186b241fa8244fecd7803; from 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 before efd58a8dd9e7a709a90ee486a4247c923d27296f; 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 builds before 4b2649b9717678aeb097893cc49f59311a1ecab0; from 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 before 443041deb5ef6a1289a99ed95015ec7442f141dc	CNA record
linux linux_kernel linux:linux_kernel	from 5.9 before 5.10.237; from 5.11 before 5.15.181; from 5.16 before 6.1.135; from 6.2 before 6.6.88; from 6.7 before 6.12.24; from 6.13 before 6.13.12; from 6.14 before 6.14.3	NVD
debian debian_linux debian:debian_linux	11.0	NVD

References

References

https://git.kernel.org/stable/c/8cf7fef1bb2ffea7792bcbf71ca00216cecc725d	patch
https://git.kernel.org/stable/c/b3088bd2a6790c8efff139d86d7a9d0b1305977b	patch
https://git.kernel.org/stable/c/855bf0aacd51fced11ea9aa0d5101ee0febaeadb	patch
https://git.kernel.org/stable/c/7f9ae060ed64aef8f174c5f1ea513825b1be9af1	patch
https://git.kernel.org/stable/c/dc81e41a307df523072186b241fa8244fecd7803	patch
https://git.kernel.org/stable/c/efd58a8dd9e7a709a90ee486a4247c923d27296f	patch
https://git.kernel.org/stable/c/4b2649b9717678aeb097893cc49f59311a1ecab0	patch
https://git.kernel.org/stable/c/443041deb5ef6a1289a99ed95015ec7442f141dc	patch
https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html	mailing-list
https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html	mailing-list

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.