pdns-recursor security updates are discontinued for bookworm - https://lists.debian.org/debian-security-announce/2025/msg00211.html

list of unpatched issues - https://security-tracker.debian.org/tracker/source-package/pdns-recursor

input from @sarthurdev:

If circinus will live on bookworm we need to find an alternate solution for this.

Also worth noting, if we build this ourselves for bookworm images. Latest pdns requires some changes in vyos-1x: https://github.com/vyos/vyos-1x/pull/4576/commits/c67ae6c6e3b978c19024b4a84cac1ec8e45cea8a