Access bypass vulnerability in Drupal Core allows JSON:API when JSON:API is in read/write mode. Only sites that have the read_only set to FALSE under jsonapi.settings config are vulnerable. This issue affects: Drupal Drupal Core 8.8.x versions prior to 8.8.8; 8.9.x versions prior to 8.9.1; 9.0.x versions prior to 9.0.1.