source: http://www.securityfocus.com/bid/22975/info

Horde IMP Webmail Client is prone to multiple input-validation vulnerabilities, including cross-site scripting and an HTML-injection issue, because the application fails to properly sanitize user-supplied input.

Attacker-supplied HTML and script code would execute in the context of the affected site, potentially allowing the attacker to steal cookie-based authentication credentials or to control how the site is rendered to the user; other attacks are also possible. 

http://www.example.com/horde/imp/search.php?edit_query=[xss] 