bug in content-disposition parsing

There is bug when Mail::Box attempts to parse Content-Disposition attributes
when vales are not quoted. Calling
$part->body->disposition->attribute('filename') on a message part with the
header:

Content-Disposition: attachment; filename=Cat.scr; modification-date="Mon,
19 Jul 2004 16:45:17 -0500"

returns "Cat.scr;" with an extra ';' attached. If the space after the ; is
removed, the file becomes "Cat.scr;modification-date=Mon,"

We are seeing numerous messages formated this way which get through filters
that look for executeable extensions

    Todd