A Broken Access Control vulnerability in MagnusBilling v7.8.5.3 allows newly registered users to gain escalated privileges by sending a crafted request to /mbilling/index.php/user/save to set their account status fom "pending" to "active" without requiring administrator approval.
https://github.com/magnussolution/magnusbilling7/commit/f886330e9e9216a3830775610a4a83f970c08e8d