Post Meta Data Manager <= 1.4.4 - Authentciated (Admin+) Multisite Privilege Escalation

The Post Meta Data Manager plugin for WordPress is vulnerable to multisite privilege escalation in all versions up to, and including, 1.4.4. This is due to the plugin not properly verifying the existence of a multisite installation prior to allowing user meta to be added/modified. This makes it possible for authenticated attackers, with Administrator-level access and above, to gain elevated privileges on subsites that would otherwise be inaccessible.