The $sortby parameter passed to 'masort' function in file
lib/functions.php isn't properly sanitized before being used in
a call to create_function() at line 1080. This can be exploited
to inject and execute arbitrary PHP code. The only possible
attack vector is when handling the 'query_engine' command, in
which input passed through $_REQUEST['orderby'] is passed as
$sortby parameter to 'masort' function.