I'm on the latest version of Mojave 10.14.4 (18E226), Darwin 18.5.0 on a 2012 Mac Pro. The system has become totally unusable for any sudo commands. It gets stuck indefinitely whenever I fire a sudo. Moreover, remote screen sharing has also stopped working. It was working fine before the restart. I even turned off the firewall after restarting, but remote screen sharing still doesn't work. SSH works though.
I came across this bug on Mac OS 10.12.4 on multiple forums. Most solutions involve modifying the sudoers file but that involved firing a sudo command and "waiting it out", but I've waited hours without any success!
Not sure if this is connected, but I recently removed administrator privileges for a user (from System Preferences > Users & Groups). The system asked for a restart for changes to take effect. I restarted and this bug kicked in.