rpc.walld (wall daemon) for Solaris 2.6 through 9 allows local users to send messages to logged on users that appear to come from arbitrary user IDs by closing stderr before executing wall, then supplying a spoofed from header.
https://exchange.xforce.ibmcloud.com/vulnerabilities/11608
http://www.securitytracker.com/id?1006682
http://www.securitytracker.com/id?1005882
http://www.securityfocus.com/bid/6509
http://sunsolve.sun.com/search/document.do?assetkey=1-26-51980-1