Apple has released an update to their OS X operating system for Macs and to iOS for iPhones and iPads.  These updates fix a serious security flaw that opens the door for your devices and your personal data to be compromised.  You should update everything now.  You can read about the security problem here.

On your Mac, click the Apple icon on the left of your menu bar and select Software Updates.

On your iPhone or iPad, go to the Settings app, select General and Software Updates.