phpBB < 2.0.10

Summary
The remote host is running a version of phpBB older than 2.0.10. phpBB contains a flaw that allows a remote cross site scripting attack. This flaw exists because the application does not validate user-supplied input in the 'search_author' parameter. This version is also vulnerable to a HTTP response splitting vulnerability which permits the injection of CRLF characters in the HTTP headers.
Solution
Upgrade to 2.0.10 or later.