A flaw was found in Aardvark-dns versions 1.12.0 and 1.12.1. They contain a denial of service vulnerability due to serial processing of TCP DNS queries. This flaw allows a malicious client to keep a TCP connection open indefinitely, causing other DNS queries to time out and resulting in a denial of service for all other containers using aardvark-dns.
https://github.com/containers/aardvark-dns/pull/503
https://github.com/containers/aardvark-dns/issues/500