The ImageMagick Engine plugin for WordPress is vulnerable to deserialization of untrusted input via the 'cli_path' parameter in versions up to, and including 1.7.5. This makes it possible for unauthenticated users to call files using a PHAR wrapper, granted they can trick a site administrator into performing an action such as clicking on a link, that will deserialize and call arbitrary PHP Objects that can be used to perform a variety of malicious actions granted a POP chain is also present. It also requires that the attacker is successful in uploading a file with the serialized payload.
https://www.wordfence.com/threat-intel/vulnerabilities/id/4a2ca2f0-1d4a-4614-86ba-a46e765f4a9f
https://github.com/orangelabweb/imagemagick-engine/blob/v.1.7.2/imagemagick-engine.php#L529
https://github.com/orangelabweb/imagemagick-engine/blob/1.7.4/imagemagick-engine.php#L529