Adobe has released several security improvements to Flash Player. The latest release is version 11.3. Mac OS X comes with a silent updater, meaning it will download and install any updates without interrupting what the user is doing i.e. an annoying prompt to reboot your machine. Users will need to choose to accept the silent updates in the first place.
Note for Mac OS X users: All future Flash Player releases for Mac OS X will only work with Gatekeeper. Read more about Gatekeeper and why developers will need to use a Developer ID to digitally sign their software for the Mac App Store to protect end-users from malicious apps.
Adobe is also running this latest Flash Player 11.3 version as a restricted process (sandboxing) within Windows and Mac OS X, which makes it very difficult for a hacker to engineer a code bug into a working exploit.
I have though seen several reports online in the past three days claiming that this Flash Player update crashes the latest version of Mozilla Firefox, but only if the user is using Protected Mode (sandboxing). Until this is fixed, I suggest Firefox users disable the Flash Player Plugin: Tools > Add-ons > Plugins > Shockwave Flash. Alternatively you can disable the Firefox Protected Mode.
Safe surfing folks!