The SKT Page Builder plugin for WordPress is vulnerable to arbitrary file uploads due to a missing capability check on the 'addLibraryByArchive' function in all versions up to, and including, 4.6. This makes it possible for authenticated attackers, with subscriber-level access and above, to upload arbitrary files that make remote code execution possible.
https://plugins.trac.wordpress.org/browser/skt-builder/trunk/sktbuilder.php#L960