This message is only applicable for: WordPress developers and those who have an account on WordPress.org site (forums, codex, etc). Or those who have any of the plugins mentioned below.
Earlier today the WordPress team noticed suspicious commits to several popular plugins (AddThis, WPtouch, and W3 Total Cache) containing cleverly disguised backdoors. We determined the commits were not from the authors, rolled them back, pushed updates to the plugins, and shut down access to the plugin repository while we looked for anything else unsavory.
We’re still investigating what happened, but as a prophylactic measure we’ve decided to force-reset all passwords on WordPress.org. To use the forums, trac, or commit to a plugin or theme, you’ll need to reset your password to a new one. (Same for bbPress.org and BuddyPress.org.)
As a user, make sure to never use the same password for two different services, and we encourage you not to reset your password to be the same as your old one.
Second, if you use AddThis, WPtouch, or W3 Total Cache and there’s a possibility you could have updated in the past day, make sure to visit your updates page and upgrade each to the latest version.