Christian Seiler prepared new packages for lxc which fixed the following
security problems:

CVE-2015-1331
  Roman Fiedler discovered a directory traversal flaw in LXC when
  creating lock files. A local attacker could exploit this flaw to
  create an arbitrary file as the root user.

CVE-2015-1334
  Roman Fiedler discovered that LXC incorrectly trusted the container's
  proc filesystem to set up AppArmor profile changes and SELinux domain
  transitions. A malicious container could create a fake proc
  filesystem and use this flaw to run programs inside the container
  that are not confined by AppArmor or SELinux.

For the wheezy-backports distribution the problems have been fixed in
version 1.0.6-6+deb8u1~bpo70+1.