PowerDNS Authoritative Server 4.1.0 up to 4.1.4 inclusive and PowerDNS Recursor 4.0.0 up to 4.1.4 inclusive are vulnerable to a packet cache pollution via crafted query that can lead to denial of service.
https://doc.powerdns.com/recursor/security-advisories/powerdns-advisory-2018-06.html
https://doc.powerdns.com/authoritative/security-advisories/powerdns-advisory-2018-05.html