GHSA-9GM5-9RFH-M6VX CoreDNS DoH/DoQ/gRPC bypass UPDATE rejection enforced on UDP/TCP

Summary CoreDNS accepted RFC 2136 UPDATE messages over DoH, DoH3, DoQ, and DNS-over-gRPC, then allowed the proxy/forward plugin to send them unchanged to an upstream DNS server. UDP, TCP, and DoT rejected the same opcode before plugin dispatch. If an update-capable upstream trusts CoreDNS's sourc...