BUG #16531: listen_addresses wide open?

The following bug has been logged on the website:

Bug reference:      16531
Logged by:          R F
Email address:      bee.lists@gmail.com
PostgreSQL version: 10.6
Operating system:   CentOS 7
Description:

I only had this in postgresql.conf:

listen_adresses = '192.168.1.50'

The machine was properly functioning on 'localhost' in an application I had
on the same machine.

In pg_hba.conf:

local   all             all                                     trust
host    all             all             127.0.0.1/32            trust

With these directives, the machine, from what I understand, shouldn't be
able to reach into localhost.