The AI Engine plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the rest_simpleFileUpload() function in versions 2.9.3 and 2.9.4. This makes it possible for authenticated attackers, with Subscriber-level access and above, to upload arbitrary files on the affected site's server when the REST API is enabled, which may make remote code execution possible.
https://plugins.trac.wordpress.org/changeset/3329842/ai-engine/trunk/classes/api.php
https://plugins.trac.wordpress.org/browser/ai-engine/tags/2.9.3/classes/modules/files.php#L332
https://plugins.trac.wordpress.org/browser/ai-engine/tags/2.9.3/classes/api.php#L673