Unbound 1.18.0 introduced a feature that removes EDE records from
responses with size higher than the client's advertised buffer size.
Before removing all the EDE records however, it would try to see if
trimming the extra text fields on those records would result in an
acceptable size while still retaining the EDE codes. Due to an
unchecked condition, the code that trims the text of the EDE records
could loop indefinitely. This happens when Unbound would reply with
attached EDE information on a positive reply and the client's buffer
size is smaller than the needed space to include EDE records.
The vulnerability can only be triggered when the 'ede: yes' option
is used; non default configuration.