attach.c in LXC 1.1.2 and earlier uses the proc filesystem in a container, which allows local container users to escape AppArmor or SELinux confinement by mounting a proc filesystem with a crafted (1) AppArmor profile or (2) SELinux label.
This entry has been deprecated. It was originally used for organizing the Development View (CWE-699) and some other views, but it introduced unnecessary complexity and depth to the resulting tree.