A cross-site scripting issue has been found in the web interface of PowerDNS Recursor from 4.0.0 up to and including 4.0.6, where the qname of DNS queries was displayed without any escaping, allowing a remote attacker to inject HTML and Javascript code into the web interface, altering the content.
https://doc.powerdns.com/recursor/security-advisories/powerdns-advisory-2017-05.html