It was found that multiple "expired" flows can take up the memory resource of CONFIG DS which leads to CONTROLLER shutdown.
Acknowledgments: Name: Vaibhav Hemant Dixit
Statement: OpenDaylight was released as a technical preview in Red Hat Openstack Platform versions 12 and under. Additionally, upstream have released an advisory outlining recommended actions, they will not be patching against this Denial of Service vector.
External References: https://lists.opendaylight.org/pipermail/opendaylight-announce/2018-January/000027.html