App.Actions.MAIL_ACC.toggle_unlimited_feature = function(evt) {
    var elm = $(evt.target);
    var ref = elm.prev('.vst-input');
    if (!$(ref).data('checked')) {
        App.Actions.MAIL_ACC.enable_unlimited(ref, elm);
    }
    else {
        App.Actions.MAIL_ACC.disable_unlimited(ref, elm);
    }
}
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.