PlanSo Forms <= 2.6.3 - Authenticated Stored Cross-Site Scripting

The PlanSo Forms WordPress plugin through 2.6.3 does not escape the title of its Form before outputting it in attributes, allowing high privilege users such as admin to set XSS payload in it, even when the unfiltered_html is disallowed, leading to an Authenticated Stored Cross-Site Scripting issue.