source: https://www.securityfocus.com/bid/8883/info
It has been reported that Apache Cocoon may be prone to a directory traversal vulnerability that may allow an attacker to traverse outside the server root directory by using '/./../' character sequences. The issue is caused by insufficient sanitization of user-supplied input to the "filename" parameter in the sample "view-source" script.
This vulnerability may be successfully exploited to gain sensitive information about a vulnerable host that could be used to launch further attacks against the system.
Apache Cocoon version 2.1 and 2.2 before 22 Oct 2003 have been reported to be affected by this issue, however other versions may be affected as well.
http://www.example.com:8888/samples/view-source?filename=../../../[existing_file]