It's applicable to software, but it's not a good software license due to reservation of patent rights. CC was designed for scientific publications, in that context reservation of patent rights has an understandable meaning, but when applied to software it takes a very different unintended meaning.
(I also consider anything that fits the Open Source Definition to be "open source" and differentiate things actually approved by the OSI as "OSI certified", which should in principle be a subset of "open source".)