Adobe recently added automatic update notifications to Flash Player, via a System Preferences pane, and it’s none too soon, since the critical vulnerability fixed by Flash Player 10.3.181.26 is, according to the non-profit group Shadowserver, being exploited in the wild on a fairly large scale. In other words, you really want to update to the latest Flash Player right away, and use the automatic update notification to stay up to date. If you’re using a PowerPC-based Mac that can’t run the latest Intel-only Flash Player version, it’s probably best to rely on ClickToFlash and load Flash elements only on select sites that you absolutely trust.
If you’re using a version of Flash prior to 10.3.181.14, when automatic notifications were first added, you can determine what version of Flash Player you do have by visiting the Adobe Flash Player page. Then download the latest version from the Adobe Flash Player Download page. (Free, 6.08 MB)