PowerDNS Authoritative Server 4.5.0 before 4.5.1 allows anybody to crash the process by sending a specific query (QTYPE 65535) that causes an out-of-bounds exception.
https://doc.powerdns.com/authoritative/security-advisories/powerdns-advisory-2021-01.html
https://doc.powerdns.com/authoritative/security-advisories/index.html