CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's implementation of Multipath TCP (MPTCP), specifically in the handling of the local_id during the MP_JOIN reconstruction process. An attacker can exploit this flaw by sending concurrent MP_JOIN SYN packets, leading to the corruption of subflow bookkeeping and potentially allowing for unauthorized access or manipulation of network connections. Organizations utilizing Linux systems with MPTCP should prioritize addressing this vulnerability to safeguard their network integrity.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: mptcp: fix uninitialized local_id in syncookie MP_JOIN reconstruction mptcp_token_join_cookie_init_state() restores remote_nonce, local_nonce, backup, join_id, token and msk from the saved cookie entry when rebuilding the request socket for a MP_JOIN 4th-ACK handled under SYN cookies, but it does not restore local_id, even though the SYN path saved it. subflow_ulp_clone() then reads that uninitialized field and stores it as the joined subflow's address-ID. Because the request-sock slab is SLAB_TYPESAFE_BY_RCU and not zeroed on allocation, the value is the stale byte of a previously freed request socket, which an off-path peer can influence by sending concurrent MP_JOIN SYNs. This corrupts the path manager's id-based subflow bookkeeping for the connection. Restore subflow_req->local_id from the cookie entry, as done for the other fields.