Popup Builder by OptinMonster – WordPress Popups for Optins, Email Newsletters and Lead Generation <= 2.16.1 - Authenticated (Contributor+) Stored Cross-Site Scripting
The Popup Builder by OptinMonster – WordPress Popups for Optins, Email Newsletters and Lead Generation plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘campaign_id’ parameter in versions up to, and including, 2.16.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.