Fixing calling payload

Author: msutovsky-r7

modules/exploits/multi/http/wondercms_rce.rb

@@ -158,7 +158,7 @@ def exploit
 
     send_request_cgi!({
       'method' => 'GET',
-      'uri' => normalize_uri(target_uri.path, '/themes/f.php')
+      'uri' => normalize_uri(target_uri.path, "/themes/#{@payload_filename}")
     })
   end
 end