Not long ago WordPress released its version 2.8.1, but there has been another update. WordPress 2.8.2 was released today as a security patch to fix the possible exploit.
WordPress 2.8.2 fixes an XSS vulnerability. Comment author URLs were not fully sanitized when displayed in the admin. This could be exploited to redirect you away from the admin to another site, as said on WordPress Official Blog.
It is strongly recommend that you upgrade your WordPress either automatically from your WordPress admin panel, or download WordPress 2.8.2.