WordPress 3.1.3  has been released and it contains security fixes and enhancements.
- Various security hardening by Alexander Concha .
- Taxonomy query hardening by John Lamansky .
- Prevent sniffing out user names of non-authors by using canonical redirects. Props Verónica Valeros .
- Media security fixes by Richard Lundeen of Microsoft , Jesse Ou of Microsoft , and Microsoft Vulnerability Research .
- Improves file upload security on hosts with dangerous security settings.
- Cleans up old WordPress import files if the import does not finish.
- Introduce “clickjacking” protection in modern browsers on admin and login pages.