It was reported that under certain conditions (when live migrations fails), an attacker can access other VMs volumes, which under normal conditions he should not be able to access:
CVE has been assigned here: http://seclists.org/oss-sec/2015/q1/990
No patches are available at the time of writing.
Created openstack-nova tracking bugs for this issue:
Affects: fedora-all [bug 1205314]
Affects: openstack-rdo [bug 1205315]