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 poc filesystem with a crafted (1) AppArmor profile or (2) SELinux label. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-1334