source: http://www.securityfocus.com/bid/27461/info
 
WebCalendar is prone to multiple HTML-injection and cross-site scripting vulnerabilities because the application fails to properly sanitize user-supplied input before using it in dynamically generated content.
 
Attacker-supplied HTML and script code would run in the context of the affected site, potentially allowing an attacker to steal cookie-based authentication credentials. The attacker could also exploit the HTML-injection issues to control how the site is rendered to the user; other attacks are also possible.
 
These issues affect WebCalendar 1.1.6; other versions may also be vulnerable. 

http://www.example.com/search.php?adv=>"&#039;><img%20src%3D%26%23x6a;%26%23x61;%26%23x76;%26%23x61;%26%23x73;%26%23x63;%26%23x72;%26%23x69;%26%23x70;%26%23x74;%26%23x3a;alert(%26quot;XSS%26quot;)>