The popup-builder plugin before 3.64.1 for WordPress allows information disclosure and settings modification, leading to in-scope privilege escalation via admin-post actions to com/classes/Actions.php. By sending a POST request to wp-admin/admin-post.php, an authenticated attacker with minimal (subscriber-level) permissions can modify the plugin's settings to allow arbitrary roles (including subscribers) access to plugin functionality by setting the action parameter to sgpbSaveSettings, export a list of current newsletter subscribers by setting the action parameter to csvfile, or obtain system configuration information including webserver configuration and a list of installed plugins by setting the action parameter to sgpbsysteminfo.

An XSS vulnerability in the popup-builder plugin before 3.64.1 for WordPress allows remote attackers to inject arbitrary JavaScript into existing popups via an unsecured ajax action in com/classes/Ajax.php. It is possible for an unauthenticated attacker to insert malicious JavaScript in several of the popup's fields by sending a request to wp-admin/admin-ajax.php with the POST action parameter of sgpbautosave and including additional data in an allPopupData parameter, including the popup's ID (which is visible in the source of the page in which the popup is inserted) and arbitrary JavaScript which will then be executed in the browsers of visitors to that page. Because the plugin functionality automatically adds script tags to data entered into these fields, this injection will typically bypass most WAF applications.