An issue was discovered in adns before 1.5.2. It hangs, eating CPU, if a compression pointer loop is encountered.
lists.opensuse.org/opensuse-security-announce/2020-06/msg00037.html
www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git
www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git%3Ba=blob%3Bf=changelog
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TRVHN3GGVNQWAOL3PWC5FLAV7HUESLZR/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UGFZ4SPV6KFQK6ZNUZFB5Y32OYFOM5YJ/
www.chiark.greenend.org.uk/pipermail/adns-announce/2020/000004.html