I'm not going to link to the post that exposed it (as it tells how to take advantage of it), but there is a security flaw in Blogrolling that needs to be addressed. In the meantime, you might want to go ahead and backup your blogroll.
UPDATE: A patch has been put in place. That being said, probably a wise idea to back up your Blogroll, nonetheless. You can download it to your local computer as an file once you login to Blogrolling.