Temporary Login Without Password 1.5 - 1.9.8 - Multisite Subsite Admin+ Network Super Admin Privilege Escalation

Description

The plugin does not verify that the user requesting a temporary login holds network super admin rights before granting the new account those rights, allowing an administrator of a single site on a multisite network to take over the whole network. The same missing check also allows an existing account, including the attacker's own, to be promoted.