If you're hosting your own WordPress (or any other solution, actually), you really should be keeping an eye for any updates. WP is a popular hacker target, even waiting a day after an announcement can be enough to get hacked. Thanks to Muprhy's law, such an announcement will definitely come when you're on vacation somewhere.

That's, of course, assuming that such an announcement is made in the first place. Last year the timthumb bug was being exploited and not all theme download sites bothered to alert the users that the themes were vulnerable.