LinuX Containers userspace utilities
Previous versions of lxc-attach ran a shell or the specified command without allocating a pseudo terminal making it vulnerable to input faking via a TIOCSTI ioctl call.
Remote attackers can escape the container and perform unauthorized modifications.
There is no know workaround at this time.
All LXC users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-emulation/lxc-2.0.7"