Vulnerability in WordPress Could Allow Cross-Domain Script Execution

Executive Summary

Microsoft is providing notification of the discovery and remediation of a vulnerability affecting WordPress version 3.1.2 and earlier, both as the cloud service from WordPress.com as well as the installable software available from WordPress.org. Microsoft discovered and disclosed the vulnerability under coordinated vulnerability disclosure to the affected vendor, WordPress. WordPress has remediated the vulnerability.

A vulnerability exists in the way that WordPress previously implemented protection against cross site scripting and content-type validation. An attacker could exploit this vulnerability to achieve script execution.

Microsoft Vulnerability Research reported this issue to and coordinated with WordPress to ensure remediation of this issue. For information on this issue from WordPress, please see WordPress News: WordPress 3.1.3 (and WordPress3.2 Beta 2)

Mitigating Factors

• An attacker who successfully exploited this vulnerability could execute scripts on other parties’ WordPress blogs in the same domain. In order for this attack to be successful all targets require an active and authenticated session with the target blog.