Four-year-old comment security bug affects 86 percent of WordPress sites | Ars Technica

This article a great reminder as to why you should always keep your WordPress install updated with the latest version. If you’re running the latest version of WordPress (currently 4.0.1), the exploit discussed below does not apply to you:

A Finnish IT company has uncovered a bug in WordPress 3 sites that could be used to launch a wide variety of malicious script-based attacks on site visitors’ browsers. Based on current WordPress usage statistics, the vulnerability could affect up to 86 percent of existing WordPress-powered sites. The vulnerability, discovered by Jouko Pynnonen of Klikki Oy, allows an attacker to craft a comment on a blog post that includes malicious JavaScript code. On sites that allow comments without authentication—the default setting for WordPress—this could allow anyone to post malicious scripts within comments that could target site visitors or administrators. ~Ars Technica