Gutenberg Template Library & Redux Framework <= 4.2.1 - Incorrect Authorization Leading to Arbitrary Plugin Installation and Post Deletion

The Gutenberg Template Library & Redux Framework plugin <= 4.2.12 for WordPress used an incorrect authorization check in the REST API endpoints registered under the “redux/v1/templates/” REST Route in “redux-templates/classes/class-api.php”. The `permissions_callback` used in this file only checked for the `edit_posts` capability which is granted to lower-privileged users such as contributors, allowing such users to install arbitrary plugins from the WordPress repository and edit arbitrary posts.