A vulnerability was discovered in DNS resolver of knot resolver before version 4.1.0 which allows remote attackers to downgrade DNSSEC-secure domains to DNSSEC-insecure state, opening possibility of domain hijack using attacks against insecure DNS protocol.
https://www.knot-resolver.cz/2019-07-10-knot-resolver-4.1.0.html
https://lists.debian.org/debian-lts-announce/2024/04/msg00017.html