The open-source WordPress content management system is once again being updated due to critical security vulnerabilities. Late on May 6, tens of millions of WordPress site administrators around the world were greeted by an all too familiar email from WordPress, with the subject line: "Your site has updated to WordPress 4.2.2."
Ever since the WordPress 3.7 release in October 2013, WordPress has provided its self-hosted users with an automated security update mechanism. The hosted WordPress.com service also automatically applies updates.
Among the new WordPress 4.2.2 security updates is one for the Genericons icon font package, which has a cross-site scripting (XSS) vulnerability risk. Genericons are used in multiple WordPress plug-ins and themes and are widely deployed. WordPress credits security firm Netsparker with reporting the Genericons vulnerability, which is also identified as CVE-2015-3429. According to Netsparker, it first contacted the WordPress security team about the issue on April 22. The actual flaw was present only in an example.html file left in the Genericons folder for a WordPress theme installation.
"By exploiting a cross-site scripting vulnerability the attacker can hijack a logged in user's session," Netsparker warns in its security advisory. "This means that the malicious hacker can change the logged in user's password and invalidate the session of the victim while the hacker maintains access."
Another major security vulnerability fix in WordPress 4.2.2 is actually a second attempt at patching a flaw that WordPress 4.2.1 was supposed to have fixed. On April 27, WordPress 4.2.1 was released, fixing a critical XSS comment flaw vulnerability that exposed sites to risk.
"Version 4.2.2 also improves on a fix for a critical cross-site scripting vulnerability introduced in 4.2.1," the WordPress 4.2.2 release note states.
WordPress developers have also taken measures in WordPress 4.2.2 to limit the risk of potential XSS issues when using the visual editor.
WordPress 4.2.2 is the third automatic update in as many weeks pushed out to fix security vulnerabilities. The WordPress 4.2.1 update was released April 27, while WordPress 4.1.2 was released on April 22. In all three cases, XSS vulnerabilities were fixed.
XSS flaws have long been a challenge for Web application developers. In 2013, IBM identified XSS as being the top Web application vulnerability from 2009 until 2013.
Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.