Race condition in the L2TPv3 IP Encapsulation feature in the Linux kernel before 4.8.14 allows local users to gain privileges or cause a denial of service (use-after-free) by making multiple bind system calls without properly ascertaining whether a socket has the SOCKZAPPED status, related to net/l2tp/l2tpip.c and net/l2tp/l2tp_ip6.c.