The Knowledge Building WordPress plugin before 0.7.3 does not sanitise and escape comments submitted through its reply feature, and publishes them without moderation, allowing unauthenticated users to perform Stored Cross-Site Scripting attacks against any visitor of the affected posts, including administrators.
The Knowledge Building WordPress plugin before 0.7.3 does not escape several user-supplied values before echoing them back in the response of an AJAX action available to unauthenticated users, and serves that response as HTML, leading to a Reflected Cross-Site Scripting.