powerdns: denial of service

Two issues have been found in PowerDNS Authoritative Server allowing a
remote, unauthenticated attacker to cause an abnormal load on the
PowerDNS backend by sending crafted DNS queries, which might result in a
partial denial of service if the backend becomes overloaded. SQL
backends for example are particularly vulnerable to this kind of
unexpected load if they have not been dimensioned for it.

• CVE-2016-5426

PowerDNS Authoritative Server accepts queries with a qname’s length
larger than 255 bytes.

• CVE-2016-5427

PowerDNS Authoritative Server does not properly handle dot inside labels.