Interaction error in OpenStack Nova and Neutron before Havana 2013.2.1 and icehouse-1 does not validate the instance ID of the tenant making a request, which allows remote tenants to obtain sensitive metadata by spoofing the device ID that is bound to a port, which is not properly handled by (1) api/metadata/handler.py in Nova and (2) the neutron-metadata-agent (agent/metadata/agent.py) in Neutron.
https://review.openstack.org/#/c/61439/1/neutron/agent/metadata/agent.py
https://review.openstack.org/#/c/61428/2/nova/api/metadata/handler.py
https://bugs.launchpad.net/neutron/+bug/1235450
http://www.securityfocus.com/bid/64250
http://www.openwall.com/lists/oss-security/2013/12/11/8