The plugin does not sanitize or escape form fields before outputting it in the List, which could allow high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed.
Navigate to WP Ticket > Forms > edit layout of “Open a Ticket” or “Search Tickets” > on “Editing Form” Setting menu. Select a form field and you can edit the “Label” with a cross-site scripting (XSS) payload such as v < 5.10.3 - "> v <= 5.10.3 - " style=animation-name:rotation onanimationstart=alert(/XSS/)// All of the parameters on the “Editing Form” are vulnerable. To trigger the XSS payload, refresh the “Editing Form” page.