Version 2:20.2.0-1 of neutron is marked for autoremoval from testing on Tue 01 Nov 2022. It depends (transitively) on python-avro, affected by #1020129. You should try to prevent the removal by fixing these RC bugs.
OpenStack Neutron before 16.4.1, 17.x before 17.1.3, and 18.0.0 allows hardware address impersonation when the linuxbridge driver with ebtables-nft is used on a Netfilter-based platform. By sending carefully crafted packets, anyone in control of a server instance connected to the virtual switch can impersonate the hardware addresses of other systems on the network, resulting in denial of service or in some cases possibly interception of traffic intended for other destinations.