Lotus Domino server 5.0.9a and earlier allows remote attackers to bypass security restrictions and view Notes database files and possibly sensitive Notes template files (.ntf) via an HTTP request with a large number of "+" characters before the .nsf file extension, which are converted to spaces by Domino.
http://www.securityfocus.com/bid/4022
http://www.nextgenss.com/papers/hpldws.pdf
http://www.iss.net/security_center/static/8072.php
http://marc.info/?l=bugtraq&m=101286525008089&w=2