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.
cmanager 0.32 does not properly enforce nesting when modifying cgroup properties, which allows local users to set cgroup values for all cgroups via unspecified vectors.
The lxc-sshd template (templates/lxc-sshd.in) in LXC before 1.0.0.beta2 uses read-write permissions when mounting /sbin/init, which allows local users to gain privileges by modifying the init file.