Clemens Fries reported that, when using Cinnamon, it was possible to bypass the screensaver lock:
http://seclists.org/oss-sec/2014/q1/327
An attacker with physical access to the machine could use this flaw to take over the locked desktop session.
A patch is currently not yet available.
apparmorparser in the apparmor package before 2.8.95~2430-0ubuntu5.1 in Ubuntu 14.04 allows attackers to bypass AppArmor policies via unspecified vectors, related to a "miscompilation flaw."
End of life: 4/2/2019, End of support: 4/2/2019, Latest version: 14.04.6
End of life: 4/2/2019, End of support: 4/2/2019, Latest version: 14.04.6