Popup Builder <= 4.3.6 - Sensitive Information Exposure via Imported Subscribers CSV File

The Popup Builder plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 4.3.6 via the Subscribers Import feature. This makes it possible for unauthenticated attackers to extract sensitive data after an administrator has imported subscribers via a CSV file. This data may include the first name, last name, e-mail address, and potentially other personally identifiable information of subscribers.