The Popup Maker – Boost Sales, Conversions, Optins, Subscribers with the Ultimate WP Popup Builder plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 1.22.0. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for authenticated attackers, with editor-level access and above, to install and activate an arbitrary plugin from an attacker-controlled URL, leading to remote code execution. Exploitation requires that a valid Popup Maker Pro license is active on the target site and that Popup Maker Pro is not yet installed, as these conditions are necessary for the legacy v1/connect/info endpoint to issue the bearer token used to satisfy the install endpoint's only non-spoofable validation check.