New RHEL vulnerability early may 2013

I hear there is a new RHEL/CentOS vulnerability out there that affects all builds.
I don't know where to go look, and google is not helping.

Is this something I need to worry about patching myself, or are you interworx folks on this?:cool:

Will I have to reboot the server for the update to take effect? I heard that too. Sorry for speculation.