Race condition in Tunnelblick 3.3beta20 and earlier allows local users to kill unintended processes by waiting for a specific PID value to be assigned to a target process.
http://www.openwall.com/lists/oss-security/2012/08/14/1
http://code.google.com/p/tunnelblick/issues/detail?id=212
http://archives.neohapsis.com/archives/fulldisclosure/2012-08/0122.html