NSEC3 closest-encloser proof validation enters unbounded loop on cross-zone responses

The NSEC3 closest-encloser proof validation in hickory-net's DnssecDnsHandle walks from the QNAME up to the SOA owner name, building a list of candidate encloser names. The iterator used assumes the QNAME is a descendant of the SOA owner, terminating only when the current candidate equals the SOA...