Yet again, there is a new version of Flash (10.1.85.3) that fixes a critical vulnerability. Been there done that, just last month in fact.
Here are my Defensive Computing suggestions for dealing with the update to Flash.
Internet Explorer users: Remove the old Adobe Flash Player via the Control Panel (Active X version of it), then download the installer program for the new version from here. Shut down IE, then run the installer.
Windows Firefox users: Remove the old Adobe Flash Player via the Control Panel (Plugin version of it), then download the installer program for the new version from here. Shut down Firefox, then run the installer.
Google Chrome users: To see the installed version of Chrome, click on the wrench, then About Google Chrome. Most likely the first three numbers will be 6.0.472. If the last number is 62, you're done, your copy of Chrome self-updated and the latest copy of Flash came along for the ride. If the last number is less than 62 then Chrome should indicate that a new version is available and offer a button to click to update.
Regardless of the browser you use, you can verify that all went well at Adobe's flash tester page (they don't call it that).
The problem with this, at least for me, is that the address of the page is impossible remember. So, I created a cheat-sheet website, flashtester.org, with the Adobe tester page URL right at the top. Can't miss it.
FlashTester.org is a single small page, all text, no ads. It has some other useful notes about Flash, including links about Flash Cookies, a history of Flash versions and multiple links to the IE and Firefox installers for the Flash Player.
As I wrote recently, you may also want to install the Flashblock extension, available for Firefox and Chrome.
The buggy version of Flash is also included with Adobe Acrobat. I am not aware of any defensive measures for this other than waiting for an update from Adobe.
Finally, the buggy version of Flash is also included in the Adobe Reader and will be for bit more. The safest option for viewing PDF files is to use software other than the Adobe Reader. There are many to chose from, in fact, they hearken back to a time when the only issue with the Adobe Reader was that it was slow.
Oh, the good old days.
Update: If you use the portable edition of Firefox (highly recommended by the way), then you need to test for the latest copy of Flash in each instance of Firefox.
As a rule, the portable edition of Firefox picks up the same copy of Flash that Firefox does (I'm told Opera and Safari also use this version, but I don't use these browsers so I haven't verified this). However, I have run across portable copies of Firefox with their own embedded copy of Flash, mimicking the behavior of Chrome - except for the important, update aspect.