If by PDF 'data' you mean XMP metadata, then yes: CF8 ships
with a version of the iText Java library that includes classes for
reading and writing XMP in PDF. CF8's CFPDF tag uses iText under
the hood but doesn't yet allow you to use all of its functionality
via CFPDF, so you can just call the Java classes directly in order
to access iText's XMP functionality.
Examples of reading and writing XMP are given here:
http://www.adobe.com/cfusion/webforums/forum/messageview.cfm?forumid=1&catid=7&threadid=1328338
Check Ray Camden's pdfUtils CFC on riaForge: it contains a
new readXMP() method. writeXMP() is coming - the code is included
in the thread above anyhow.
If you mean form data rather than XMP data, then iText can do
that too. Check the iText docs:
http://www.1t3xt.info/api/
here's a quick form-filling example
http://www.peabrane.com/2007/3/5/pdf-templates-via-rails
and from cfSearching (who really knows iText in a CF context)
there's this example, note the use of the fdfReader iText class:
http://cfsearching.blogspot.com/2008/01/submit-pdf-form-as-fdf-with-coldfusion.html