Comment 19 for bug 1781699

This looks like a possible use-after-free so likely has a security impact (at a minimum it is a denial of service due to the crash, especially if it can be triggered remotely) - I've reported it to ISC as such who will hopefully assign a CVE and then we can fix it as a security update. For future reference, the RT #48804 contains a patch that should likely be fine for Bionic https://bugs.isc.org/Public/Ticket/Attachment/534989/331007/46719.v4_3.diff