The code in download-file.php doesn't verify the user is logged in or sanitize what files can be downloaded. This vulnerability can be used to download sensitive system files: 2 $file = $_GET['file_link']; 3 4 if (file_exists($file)) { 5 header('Content-Description: File Transfer'); 6 header('Content-Type: application/octet-stream'); 7 header('Content-Disposition: attachment; filename='.basename($file)); 8 header('Content-Transfer-Encoding: binary'); 9 header('Expires: 0'); 10 header('Cache-Control: must-revalidate, post-check=0, pre-check=0'); 11 header('Pragma: public'); 12 header('Content-Length: ' . filesize($file)); 13 ob_clean(); 14 flush(); 15 readfile($file);