An issue has been found in PowerDNS Authoritative Server before 3.4.11 and 4.0.2 allowing a remote, unauthenticated attacker to cause a denial of service by opening a large number of TCP connections to the web server. If the web server runs out of file descriptors, it triggers an exception and terminates the whole PowerDNS process. While it's more complicated for an unauthorized attacker to make the web server run out of file descriptors since its connection will be closed just after being accepted, it might still be possible.
An issue has been found in the API component of PowerDNS Authoritative 4.x up to and including 4.0.4 and 3.x up to and including 3.4.11, where some operations that have an impact on the state of the server are still allowed even though the API has been configured as read-only via the api-readonly keyword. This missing check allows an attacker with valid API credentials to flush the cache, trigger a zone transfer or send a NOTIFY.
PowerDNS (aka pdns) Authoritative Server before 3.4.10 does not properly handle a . (dot) inside labels, which allows remote attackers to cause a denial of service (backend CPU consumption) via a crafted DNS query.
PowerDNS (aka pdns) Authoritative Server before 3.4.10 allows remote attackers to cause a denial of service (backend CPU consumption) via a long qname.
PowerDNS (aka pdns) Authoritative Server 3.4.4 before 3.4.7 allows remote attackers to cause a denial of service (assertion failure and server crash) via crafted query packets.