Race Condition in Linux Kernel's Multipath TCP Implementation by The Linux Foundation

CVE-2025-40258

What is CVE-2025-40258?

A race condition was discovered in the Multipath TCP (MPTCP) implementation within the Linux kernel. The vulnerability arises when the mptcp_schedule_work() function is called, which schedules a work item that references a socket's reference count. If mptcp_worker() executes immediately after scheduling the work, it may release the reference count before the socket is confirmed to be in use, leading to a use-after-free scenario. This flaw necessitates careful handling of socket references to ensure that they remain valid throughout the execution of scheduled tasks.

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