Wordpress Developer Team has just released the WordPress 3.1.3 , an security update for all the previous versions of wordpress .

Some of the bug fixes or patches included in this version include

• 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.

You can download WordPress 3.1.3 here

Alternatively, you can upgrade the wordpress from your WordPress dashboard