Microsoft Internet Explorer 8.0 Beta 2 relies on the XDomainRequestAllowed HTTP header to authorize data exchange between domains, which allows remote attackers to bypass the product's XSS Filter protection mechanism, and conduct XSS and cross-domain attacks, by injecting this header after a CRLF sequence, related to "XDomainRequest Allowed Injection (XAI)." NOTE: the vendor has reportedly stated that the XSS Filter intentionally does not attempt to "address every conceivable XSS attack scenario."