Popup Maker < 1.16.5 - Admin+ Stored Cross-Site Scripting

The plugin does not sanitise and escape some of its Popup settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed

PoC

Popup Maker > Create Popup > Popup Settings > Triggers > Add New Cookie > Add > Cookie Time, overwrite the default ‘1 month’ with the following XSS payload: Click ‘Update’ and Save/Update the Popup. The XSS will be triggered when editing the popup again