Bug 2414465 (CVE-2025-40133)

Summary: CVE-2025-40133 kernel: mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: ---
Doc Text:
A use-after-free flaw was found in Multipath TCP in the Linux kernel in net/mptcp/ctrl.c:mptcp_active_enablecode due to concurrency problem. This flaw could allow an attacker to crash the system at device disconnect. This vulnerability could even lead to a kernel information leak problem.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2025-11-12 11:01:24 UTC 
In the Linux kernel, the following vulnerability has been resolved:

mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable().

mptcp_active_enable() is called from subflow_finish_connect(),
which is icsk->icsk_af_ops->sk_rx_dst_set() and it's not always
under RCU.

Using sk_dst_get(sk)->dev could trigger UAF.

Let's use __sk_dst_get() and dst_dev_rcu().
Comment 1 Alexander B 2025-11-13 17:03:07 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025111254-CVE-2025-40133-4d9d@gregkh/T
Comment 3 errata-xmlrpc 2026-02-02 15:25:16 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10.0 Extended Update Support

Via RHSA-2026:1727 https://access.redhat.com/errata/RHSA-2026:1727
Comment 4 errata-xmlrpc 2026-02-09 09:31:59 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:2282 https://access.redhat.com/errata/RHSA-2026:2282