An issue was discovered in Linux Containers (LXC) before 2016-02-22. When executing a program via lxc-attach, the nonpriv session can escape to the parent session by using the TIOCSTI ioctl to push characters into the terminal's input buffer, allowing an attacker to escape the container.
https://security.gentoo.org/glsa/201711-09
https://github.com/lxc/lxc/commit/e986ea3dfa4a2957f71ae9bfaed406dd6e1ffff6
http://www.securityfocus.com/bid/95404