Description
WordPress MU is prone to a cross-site scripting vulnerability because the application 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 may help the attacker steal cookie-based authentication credentials and launch other attacks. WordPress MU versions prior to 2.7 are vulnerable.
Remediation
Update to WordPress MU version 2.7 or latest
References
http://www.exploit-db.com/exploits/8196/
http://www.securityfocus.com/archive/1/501667
http://packetstormsecurity.org/files/view/75622/wordpressmuhost-xss.txt
Related Vulnerabilities
WordPress Plugin amtyThumb posts Cross-Site Scripting (8.1.3)
PHP Improper Control of Generation of Code ('Code Injection') Vulnerability (CVE-2007-4782)
Moodle Improper Authentication Vulnerability (CVE-2013-2245)
Nginx Use After Free Vulnerability (CVE-2012-1180)
WordPress Plugin Stylish Cost Calculator Cross-Site Scripting (7.0.3)