System Dashboard <= 2.8.7 - Missing Authorization to Information Disclosure (sd_global_value)

The System Dashboard plugin for WordPress is vulnerable to unauthorized access of data due to a missing capability check on the sd_global_value() function hooked via an AJAX action in all versions up to, and including, 2.8.7. This makes it possible for authenticated attackers, with subscriber-level access and above, to retrieve sensitive global value information.