It was found that a non privileged tenant can add a router interface to a shared / external network's subnet with an IP address outside the subnet's allocation pool. This can result in a Denial of Service.

Upstream issue:

https://bugs.launchpad.net/neutron/+bug/1757482

Upstream patch:

https://git.openstack.org/cgit/openstack/neutron/commit/?id=54aa6e81cb17b33ce4d5d469cc11dec2869c762d

Live-migrated instances are briefly able to inspect traffic for other instances on the same hypervisor. This brief window could be extended indefinitely if the instance's port is set administratively down prior to live-migration and kept down after the migration is complete. This is possible due to the Open vSwitch integration bridge being connected to the instance during migration. When connected to the integration bridge, all traffic for instances using the same Open vSwitch instance would potentially be visible to the migrated guest, as the required Open vSwitch VLAN filters are only applied post-migration. Versions of openstack-neutron before 13.0.0.0b2, 12.0.3, 11.0.5 are vulnerable.