CVE-2018-5710: krb5 package version issue

[Sam Hartman]

This doesn't sound like a Debian issue.
It sounds more like a disagreement between your source of vulnerability
information and Ubuntu about when a problem is fixed (or whether it
was).
I also don't see CVE-2018-5710 as a vulnerability that upstream lists as
fixed in their git history.

I would not want to take on the liability of making a comment about
whether a particular issue is fixed in a particular package version in
Ubuntu unless I prepared that version.

--Sam