CoreDNS: Unauthenticated memory exhaustion in custom transports

Summary CoreDNS parses attacker-controlled DNS section counts before validating them on DNS-over-HTTPS DoH and DoH3, DNS-over-QUIC DoQ, and DNS-over-gRPC listeners. An unauthenticated client can use DNS name compression to make one 65,533-byte request allocate more than 10 MiB while it is unpacke...