The openvswitch-agent process in OpenStack Neutron 2013.1 before 2013.2.4 and 2014.1 before 2014.1.1 allows remote authenticated users to bypass security group restrictions via an invalid CIDR in a security group rule, which prevents further rules from being applied.
https://bugs.launchpad.net/neutron/+bug/1300785
http://www.ubuntu.com/usn/USN-2255-1
http://www.openwall.com/lists/oss-security/2014/04/22/8
http://secunia.com/advisories/59533
http://lists.opensuse.org/opensuse-updates/2014-08/msg00035.html