JRun 3.0 through 4.0 allows remote attackers to read JSP source code via an encoded null byte in an HTTP GET request, which causes the server to send the .JSP file unparsed.
http://www.macromedia.com/v1/handlers/index.cfm?ID=23164
http://www.iss.net/security_center/static/9459.php
http://online.securityfocus.com/archive/1/280062
http://archives.neohapsis.com/archives/vulnwatch/2002-q2/0138.html