Unbound before 1.9.5 allows configuration injection in create_unbound_ad_servers.sh upon a successful man-in-the-middle attack against a cleartext HTTP session. NOTE: The vendor does not consider this a vulnerability of the Unbound software. create_unbound_ad_servers.sh is a contributed script from the community that facilitates automatic configuration creation. It is not part of the Unbound installation
https://security.netapp.com/advisory/ntap-20210507-0007/
https://ostif.org/our-audit-of-unbound-dns-by-x41-d-sec-full-results/
https://lists.debian.org/debian-lts-announce/2021/05/msg00007.html