An issue has been found in PowerDNS Recursor before 4.1.18, 4.2.x before 4.2.5, and 4.3.x before 4.3.5. A remote attacker can cause the cached records for a given name to be updated to the Bogus DNSSEC validation state, instead of their actual DNSSEC Secure state, via a DNS ANY query. This results in a denial of service for installation that always validate (dnssec=validate), and for clients requesting validation when on-demand validation is enabled (dnssec=process).
https://security.gentoo.org/glsa/202012-19
https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2020-07.html
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00036.html