Adobe has released an update to its Flash Player software to patch a critical zero-day vulnerability. Adobe says that "the vulnerability is being exploited in the wild in active targeted attacks designed to trick the user into clicking on a malicious file delivered in an email message," but that "The exploit targets Flash Player on Internet Explorer for Windows only."
The new version of Flash Player is 18.104.22.168. Mac users can update this software by visiting the Adobe Flash Player Download Center. You can also check which version of Flash Player you have by visiting the About Flash Player web page.