smartsearch.cgi exploit... Important

Hi,

As you know lots of customer use smartsearch.cgi search script from smartcgis.com. Its a good PPC script and we have lots of customers using it, but recently I have seen some people have found a exploit for the script and can gain shell access and download pron or spam and all kinds of things
This has all happened from users running smartsearch.cgi script.

After researching on net i found this :
http://www.securiteam.com/exploits/5AP041F8VA.html



Now I know most host have customers using this smartsearch ppc script for sure and want to know is there some patch i can use on script or server so someone cant execute some misc code /trojan etc on server.
How do we avoid it ?
Any help, tips, comments are appreciated.

Thanks