Comment 103 for bug 885027

>The mount helper was only used if udisks is not present. calibre still works out of the box on the vast majority of modern Linux distros.

Please correct me if I'm wrong,
even if you have a modern distro with udisks, if you installed calibre via the official binary install, which is recommended in the website ("Please do not use your distribution provided calibre package, as those are often buggy/outdated. Instead use the Binary install described below. ") then calibre-mount-helper gets installed automatically even if udisks is present. Doesn't matter if calibre uses it or not. Every user that followed that advise is now vulnerable to privilege escalation.