The vulnerability is related to the Linux kernel's sockmap component, where a hard-coded assumption in the call-chain expects the egress socket to be a TCP socket. However, with the introduction of redirects to non-TCP sockets in commit 122e6c79efe1 for BPF sk skb programs, attempts to send-to-egress through a non-TCP socket can lead to a crash due to an invalid downcast from sock to tcp sock, resulting in a kernel NULL pointer dereference. When attempted, the user will receive an EACCES error from send/sendto/sendmsg() syscall.