Describe CVE-2021-39356.
What is CVE-2021-39356?
The Content Staging WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and escaping via several parameters that are echo'd out via the ~/templates/settings.php file which allowed attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 2.0.1. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled..