An issue was discovered in adns before 1.5.2. It corrupts a pointer when a nameserver speaks first because of a wrong number of pointer dereferences. This bug may well be exploitable as a remote code execution.
https://www.chiark.greenend.org.uk/pipermail/adns-announce/2020/000004.html
http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git%3Ba=blob%3Bf=changelog
http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git