Description
WordPress is prone to a vulnerability that allows an attacker to gain unauthorized access to the affected application. An attacker can exploit this issue to gain administrative access to the application, which can result in total compromise of the affected application. WordPress versions prior to 2.5.1 are vulnerable.
Remediation
Update to WordPress version 2.5.1 or latest
References
http://www.cl.cam.ac.uk/~sjm217/advisories/wordpress-cookie-integrity.txt
http://www.securityfocus.com/archive/1/491356