ColdFusion is sometimes used to refer to CFML, the dynamic programming language which Adobe ColdFusion ("CF") implements, but which is also implemented by a number of alternative CFML engines - notably Open BlueDragon and Railo - each with a compatible CFML core but different advantages/focuses.
Most CFML implementations run using a Java servlet engine - ColdFusion versions 6-9 ship with JRun, but from CF10 onwards the default servlet engine is Tomcat. Open BlueDragon and Railo run on Jetty/Resin/Tomcat, though they can all use any J2EE app server. There is also a BlueDragon.NET which runs on Microsoft's .NET platform instead of Java.
The latest version, ColdFusion 10, was released in May 2012.