@Override
    protected Event doExecuteInternal(final RequestContext requestContext) {
        val webflow = casProperties.getAuthn().getX509().getWebflow();
        val endpoint = UriComponentsBuilder
            .fromUriString(casProperties.getServer().getLoginUrl())
            .port(webflow.getPort())
            .build()
            .toUriString();
        requestContext.getFlowScope().put(ATTRIBUTE_X509_CLIENT_AUTH_LOGIN_ENDPOINT_URL, endpoint);
        return null;
    }
Attribute to indicate the x509 login endpoint.
support/cas-server-support-x509-webflow/src/main/java/org/apereo/cas/web/flow/X509TomcatServletFactoryInitialAction.java