Real Networks RealServer 7.x allows remote attackers to cause a denial of service via a malformed request for a page in the viewsource directory.
https://exchange.xforce.ibmcloud.com/vulnerabilities/4587
http://archives.neohapsis.com/archives/bugtraq/2000-05/0427.html
http://archives.neohapsis.com/archives/bugtraq/2000-05/0410.html