source: https://www.securityfocus.com/bid/9575/info

The rxgoogle.cgi search script is prone to a cross-site scripting vulnerability because the software fails to sanitize user input and allows various metacharacters that may facilitate cross-site scripting attacks.

An attacker may leverage this issue to execute arbitrary code in the browser of an unsuspecting user in the context of the affected site. This may help the attacker steal cookie-based authentication credentials and launch other attacks.

http://www.example.com/cgi-bin/rxgoogle.cgi?query=%3Cscript%3Ealert%28%22XSS%22%29%3C%2Fscript%3E