CoreDNS is a DNS server written in Go. Prior to 1.14.7, the DNS-over-HTTPS, DNS-over-HTTP/3, DNS-over-QUIC, and DNS-over-gRPC request paths in plugin/pkg/doh/doh.go, core/dnsserver/serverquic.go, and core/dnsserver/servergrpc.go call dns.Msg.Unpack on attacker-controlled DNS section counts before dns.DefaultMsgAcceptFunc validates the fixed header. An unauthenticated client can use DNS name compression and excessive section counts to amplify allocation before the plugin chain, so plugin-level rate limiting cannot prevent concurrent requests from exhausting memory and terminating CoreDNS. The ordinary UDP and TCP listeners are not affected because they validate the header first. This issue is fixed in version 1.14.7.

Coredns mishandling of CI bit: CD bit response is cached and served later

What happened: If CD bit is set in query, it disables validation at remote server

What you expected to happen: CD queries may pass, but the same answer must not be served to queries without CD bit set

https://github.com/coredns/coredns/issues/6186