Race condition in OpenStack Neutron before 2014.2.4 and 2015.1 before 2015.1.2, when using the ML2 plugin or the security groups AMQP API, allows remote authenticated users to bypass IP anti-spoofing controls by changing the device owner of a port to start with network: before the security group rules are applied.
https://security.openstack.org/ossa/OSSA-2015-018.html
https://bugzilla.redhat.com/show_bug.cgi?id=1258458
https://bugs.launchpad.net/neutron/+bug/1489111