Today Apple blocked older Flash Player versions, here is their statement:
Due to security issues in older versions, Apple has updated the
web plug-in blocking mechanism to disable all versions prior to
Flash Player 18.104.22.168.
Apple will push out this block to your XProtect automatically next time your Mac comes online so if you suddenly find certain websites no longer load certain contents this is most likely why. Version 22.214.171.124 can be found here. If you have a recent version already installed you can also go to your System Preferences > Flash Player > Advanced > Updates and initiate the update from there.
Firefox also released an update putting their awesome browser at version 27. If you already use Firefox, the most private and secure web browser, you can go to the Firefox menu > About Firefox and the update will start downloading. You can also visit the Firefox website directly here.
To see what’s new in version 27 have a look at this page.
And here are the security related changes:
MFSA 2014-12 NSS ticket handling issues
MFSA 2014-11 Crash when using web workers with asm.js
MFSA 2014-10 Firefox default start page UI content invokable by script
MFSA 2014-09 Cross-origin information leak through web workers
MFSA 2014-08 Use-after-free with imgRequestProxy and image proccessing
MFSA 2014-07 XSLT stylesheets treated as styles in Content Security Policy
MFSA 2014-06 Profile path leaks to Android system log
MFSA 2014-05 Information disclosure with *FromPoint on iframes
MFSA 2014-04 Incorrect use of discarded images by RasterImage
MFSA 2014-03 UI selection timeout missing on download prompts
MFSA 2014-02 Clone protected content with XBL scopes
MFSA 2014-01 Miscellaneous memory safety hazards (rv:27.0 / rv:24.3)