Is it possible to get a file extension without knowing it?

I have a file called 94bf663a100e848fb599209af8cdc2b5.wmv. I know pathinfo will not give me the extension if I just use the name 94bf663a100e848fb599209af8cdc2b5. I believe glob is only for checking if a file exists. So is it possible to get a file extension just knowing the file name (94bf663a100e848fb599209af8cdc2b5)?