Perhaps this should be addressed but the fact it requires the user to download and open a file means it's of limited use to attackers. If you can persuade a user to do that then you needn't bother with browser exploits to get access to a user's files.
Edit: but wait, it can only access the directory the file was downloaded to? So that's almost certainly restricted to the user's download folder. That makes even less useful.
Edit: but wait, it can only access the directory the file was downloaded to? So that's almost certainly restricted to the user's download folder. That makes even less useful.