I think this was CVE-2017-6519, which was fixed a long time ago. I am closing this bug, please feel free to open a new bug if you can reproduce with a more recent version of Ubuntu. Thanks!
** CVE added: https://cve.mitre.org/cgi-bin/cvename.cgi?name=2017-6519 ** Changed in: avahi (Ubuntu) Status: New => Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1570788 Title: Makes mDNS ddos amplification attack possible To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/avahi/+bug/1570788/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs