The Stockdio Historical Chart plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'stockdio-historical-chart' shortcode in all versions up to, and including, 2.8.18 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
The Stockdio Historical Chart plugin before 2.8.1 for WordPress is affected by Cross Site Scripting (XSS) via stockdio_chart_historical-wp.js in wp-content/plugins/stockdio-historical-chart/assets/ because the origin of a postMessage() event is not validated. The stockdio_eventer function listens for any postMessage event. After a message event is sent to the application, this function sets the "e" variable as the event and checks that the types of the data and data.method are not undefined (empty) before proceeding to eval the data.method received from the postMessage. However, on a different website. JavaScript code can call window.open for the vulnerable WordPress instance and do a postMessage(msg,'*') for that object.