Apple does seem to be regularly fixing the most egregious security bugs. The troublesome part is just how many bugs there are with which an attacker could have gained complete control over the system. But that’s the “game”: for every bug fixed, there are probably a dozen others to be found of similar risk. This isn’t like to change any time soon.
Of particular note are numerous bug fixes to PHP, a programming language used for web sites. Also, fixes to OpenSSL, code signing and WebKit.
Peter G writes:
Unless you use Capture One for processing your RAW files you may update, but the update shows some strange behavior that probably Phase One has to fix.
MPG: always risks to any update for some software.