Divide-by-Zero Vulnerability in Linux Kernel Affecting MultiPath TCP Functionality

CVE-2025-68291

What is CVE-2025-68291?

A divide-by-zero vulnerability has been identified in the MultiPath TCP (MPTCP) implementation of the Linux kernel, which could lead to unexpected behavior during the fast close operation, specifically in the function mptcp_do_fastclose(). A report by syzbot indicated an occurrence of the issue during execution, necessitating the initialization of the rcv_mss variable to a safe minimum value before being utilized in the tcp_send_active_reset() call. This fix aims to enhance the stability and security of MPTCP operations, ensuring reliable performance and mitigating the risk of crashes.

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