@Override
    protected Event doExecuteInternal(final RequestContext context) {
        val attributes = context.getCurrentEvent().getAttributes();
        val warnings = (Collection<MessageDescriptor>)
            attributes.get(CasWebflowConstants.ATTRIBUTE_ID_AUTHENTICATION_WARNINGS, Collection.class, new LinkedHashSet<>());
        val found = warnings
            .stream()
            .filter(PasswordExpiringWarningMessageDescriptor.class::isInstance)
            .findAny();
        context.getFlowScope().put(ATTRIBUTE_NAME_EXPIRATION_WARNING_FOUND, found.isPresent());
        Optional.ofNullable(WebUtils.getCredential(context, Credential.class))
                .ifPresent(upc -> PasswordManagementWebflowUtils.putPasswordResetUsername(context, upc.getId()));
        return null;
    }
Attribute indicating password expiration warnings are found.
support/cas-server-support-pm-webflow/src/main/java/org/apereo/cas/pm/web/flow/actions/HandlePasswordExpirationWarningMessagesAction.java