CVE-2026-74268

In the Linux kernel, the following vulnerability has been resolved:

tcp: clear sock_ops cb flags before force-closing a child socket

A child socket inherits the listener's bpf_sock_ops_cb_flags via

sk_clone_lock(). If its setup fails in tcp_v4_syn_recv_sock() /

tcp_v6_syn_recv_sock(), the child is freed through put_and_exit, where

inet_csk_prepare_forced_close() drops the socket lock and tcp_done() runs

without it.

If BPF_SOCK_OPS_STATE_CB_FLAG was inherited, tcp_done() -> tcp_set_state()

calls tcp_call_bpf(), which expects the lock and trips sock_owned_by_me():

WARNING: include/net/sock.h:1799 at tcp_set_state+0x433/0x550

RIP: 0010:tcp_set_state+0x433/0x550 include/net/sock.h:1799

Call Trace:

<IRQ>

tcp_done+0xba/0x250 net/ipv4/tcp.c:5095

tcp_v4_syn_recv_sock+0x850/0xa50 net/ipv4/tcp_ipv4.c:1787

tcp_check_req+0xf30/0x1360 net/ipv4/tcp_minisocks.c:926

tcp_v4_rcv+0x1047/0x1b50 net/ipv4/tcp_ipv4.c:2164

</IRQ>

The child is freed before it is ever established, so it should run no

sock_ops callback. Clear its cb flags in inet_csk_prepare_for_destroy_sock(),

the common point for the IPv4, IPv6 and chtls forced-close paths and for the

MPTCP ->syn_recv_sock() failure path (dispose_child), which reaches tcp_done()

on a child that was never established too.