Security Update 2015-004 Available for OS X Mavericks & Mountain Lion
Mac users who are running OS X Mavericks and OS X Mountain Lion will find an important security update available to them. Labeled as Security Update 2015-004 1.0, the software update includes many fixes to a wide variety of potential security issues for OS X, and is therefore recommended for all Mac users running OS X 10.9.5 or OS X 10.8.5 to install.
Users who are running OS X Yosemite will find the same security fixes bundled within the OS X 10.10.3 software update, thus there is no separate security update patch available for Yosemite.