update description

modules/exploits/multi/http/joomla_http_header_rce.rb

@@ -19,7 +19,8 @@ class Metasploit3 < Msf::Exploit::Remote
           by sending an UTF-8 character. The custom created payload is then executed once the session is read
           from the databse. You also need to have a PHP version before 5.4.45 (including 5.3.x), 5.5.29 or 5.6.13.
           In later versions the deserialisation of invalid session data stops on the first error and the
-          exploit will not work.
+          exploit will not work. On Ubuntu the PHP Patch was included in versions 5.5.9+dfsg-1ubuntu4.13 and
+          5.3.10-1ubuntu3.20.
       },
       'Author'	=>
         [