WordPress 3.1.2 is now available for download. This is security update for all previous releases. WordPress version 3.1.2 fixes a vulnerability that allowed Contributor-level users to improperly publish posts. This update also fixes too much escaping for pages when using Quick Edit,Walker_PageDropdown doesn’t filter titles correctly, WP_User_Query ordered by post_count doesn’t work if prefix is not wp_ and Multiple tag queries broken.
WordPress 3.1.2 Release Note