Ticket #52205: 52205.diff

src/wp-includes/rest-api/endpoints/class-wp-rest-plugins-controller.php

@@ -209 +209 @@
          * @return true|WP_Error True if can read, a WP_Error instance otherwise.
          */
         protected function check_read_permission( $plugin ) {
+                require_once ABSPATH . 'wp-admin/includes/plugin.php';
+
                 if ( ! $this->is_plugin_installed( $plugin ) ) {
                         return new WP_Error( 'rest_plugin_not_found', __( 'Plugin not found.' ), array( 'status' => 404 ) );
                 }