Soft Lockup Vulnerability in Linux Kernel's MPTCP Protocol

CVE-2026-43029

What is CVE-2026-43029?

A vulnerability exists in the Linux kernel's MPTCP protocol that can lead to a soft lockup condition during data reception when specific flags are used. The issue arises when utilizing MSG_PEEK and MSG_WAITALL flags, preventing proper removal of the socket buffer from the receive queue. This oversight causes sk_wait_data to continuously find available data, leading to a state where actual waiting cannot occur, thus resulting in a soft lockup. A fix has been implemented to add a parameter that assists in managing socket buffers more effectively, thereby preventing infinite loops and ensuring smoother operations during data handling.

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