Popup Maker < 1.20.5 - Contributor+ Stored XSS via popupID Parameter

Description

The plugin is vulnerable to Stored Cross-Site Scripting via the ‘popupID' parameter due to insufficient input sanitization and output escaping. 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.