The Brizy – Page Builder plugin for WordPress is vulnerable to limited file uploads due to missing authorization on process_external_asset_urls function as well as missing path validation in store_file function in all versions up to, and including, 2.6.20. This makes it possible for unauthenticated attackers to upload .TXT files on the affected site's server.
https://plugins.trac.wordpress.org/browser/brizy/tags/2.6.17/editor/asset/static-file-trait.php#L44
https://plugins.trac.wordpress.org/browser/brizy/tags/2.6.17/editor/asset/media-processor.php#L27