CVE 2015-5240
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.
See the 
CVE page on Mitre.org
for more details.
