Description
WordPress is prone to a cross-site scripting vulnerability because it fails to properly sanitize user-supplied input. An attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. This can allow the attacker to steal cookie-based authentication credentials and launch other attacks. WordPress versions 3.9.x ranging from 3.9 and up to (and including) 3.9.9 are vulnerable.
Remediation
Update to WordPress version 3.9.10 or latest
References
https://www.incapsula.com/blog/incapsula-blocks-xss-vulnerability-wordpress-4-4-1.html
https://twitter.com/brutelogic/status/685105483397619713
Related Vulnerabilities
WordPress Plugin Advanced Dynamic Pricing for WooCommerce Cross-Site Request Forgery (4.1.3)
WordPress Plugin All-In-One Security (AIOS)-Security and Firewall Information Disclosure (5.1.2)
WordPress Plugin WP-Stats Multiple Vulnerabilities (2.51)
Joomla Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (CVE-2011-4937)