i no longer have the email that i got a few days ago that had at least some details, but if you want a better shot at knowing exactly what impact various newfound security holes have, your best bet is to subscribe to one of the major alerting email lists, like the one from http://www.us-cert.gov/ -- they tend to post some serious description of the possible impact of the issue and what's being patched (and the alerts are for more than just OSX).