Smash Balloon Social Post Feed < 2.19.2 - Unauthenticated Stored XSS

The Smash Balloon Social Post Feed WordPress plugin before 2.19.2 does not sanitise or escape the feedID POST parameter in its feed_locator AJAX action (available to both authenticated and unauthenticated users) before outputting a truncated version of it in the admin dashboard, leading to an unauthenticated Stored Cross-Site Scripting issue which will be executed in the context of a logged in administrator.