There are currently no known security vulnerabilities in ONOS. You can find the template demonstrating the structure of future advisories here.
[Important] [CVE-TBD] onos-of-ctl: Exception thrown while deserializing malformed packets
Packet-ins coming from the dataplane can contain truncated or malformed packets. ONOS would throw an exception while attempting to deserialize these packets, which would result in the switch being disconnected because and exception occurred in an I/O thread. This opened a DoS vulnerability in ONOS, where an attacker could send malformed packets into the network and cause ONOS to disconnect switches.
See ONOS-605 for details.
ONOS 1.0.0 Avocet is confirmed to be affected.