Even Canon's? As Kirk points out, seems unlikely that a camera with the ability to shoot raw would come with no way of actually using the raw files."IF" indeed no converter supports it, no converter supports it. The key here is 'if' as far too little about the file in question has (or can be?) answered.
What I'm saying is - new Canon 5Ds[R] may be
in fact supported by some converters. On the other hand, some cameras do not really came out, they just appeared - so those who received bootleg raw files may have no access to the necessary version of, say, DPP.