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.