Your link points to a vulnerability that could have been mitigated by putting the internal application developped with Apache Struts behind a proxy server like

Your link points to a vulnerability that could have been mitigated by putting the internal application developped with Apache Struts behind a proxy server like Nginx or GCP Identity Aware Proxy (IAP) that authenticate the request before the request is forwarded to the application server. This only applies to apps for internal use like Confluence or Jenkins, not publically accessible websites.