The selinux_ip_postroute_iptables_compat function in security/selinux/hooks.c in the SELinux subsystem in the Linux kernel before 2.6.27.22, and 2.6.28.x before 2.6.28.10, when compat_net is enabled, omits calls to avc_has_perm for the (1) node and (2) port, which allows local users to bypass intended restrictions on network traffic.  NOTE: this was incorrectly reported as an issue fixed in 2.6.27.21.