security

name	security
description	Guide Claude on securing Vaadin 25 applications with Spring Security. This skill should be used when the user asks to "add security", "add login", "create a login view", "create a login form", "use Spring Security", "secure a view", "add authentication", "add authorization", "use @RolesAllowed", "use @PermitAll", "use @AnonymousAllowed", "use @DenyAll", "use VaadinSecurityConfigurer", "add OAuth2", "use OAuth2 login", "use Google login", "use Keycloak", "use GitHub login", "add logout", "add a logout button", "use AuthenticationContext", "protect a view", "role-based access", "configure SecurityFilterChain", or needs help with view access control, login forms, OAuth2 providers, or logout handling in Vaadin Flow.
version	0.1.0

Security with Spring Security in Vaadin 25

Use the Vaadin MCP tools (search_vaadin_docs, get_component_java_api, get_component_styling) to look up the latest documentation whenever uncertain about a specific API detail. Always set vaadin_version to "25" and ui_language to "java".

When to Use This Skill vs. Others

This skill covers: Spring Security configuration with VaadinSecurityConfigurer, login views with LoginForm, view access control annotations (@AnonymousAllowed, @PermitAll, @RolesAllowed, @DenyAll), AuthenticationContext, logout handling, and OAuth2/OpenID Connect integration with providers like Google, Keycloak, GitHub, and Okta.

Use views-and-navigation instead when the question is about @Route, @Layout, AppLayout, SideNav, or URL parameters. This skill covers how to secure views, not how to create or navigate between them.

Use client-side-views instead when securing React/Hilla views with ViewConfig.loginRequired and ViewConfig.rolesAllowed. This skill covers Java/Flow view security, though the annotation-based approach also applies to @BrowserCallable endpoints.

Setting Up Spring Security

Add the Spring Security starter dependency:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>

Create a security configuration class that uses VaadinSecurityConfigurer:

@EnableWebSecurity
@Configuration
public class SecurityConfig {

    @Bean
    SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http.with(VaadinSecurityConfigurer.vaadin(), configurer -> {
            configurer.loginView(LoginView.class);
        });
        return http.build();
    }

    @Bean
    public UserDetailsManager userDetailsManager() {
        // WARNING: In-memory users for development only.
        // Use JDBC, LDAP, or OAuth2 in production.
        var user = User.withUsername("user")
                .password("{noop}user")
                .roles("USER")
                .build();
        var admin = User.withUsername("admin")
                .password("{noop}admin")
                .roles("ADMIN")
                .build();
        return new InMemoryUserDetailsManager(user, admin);
    }
}

VaadinSecurityConfigurer.vaadin() automatically handles:

• CSRF — enabled with exemptions for Vaadin internal requests
• Logout — configured with Vaadin-aware logout handlers
• Request cache — Vaadin-specific request cache for redirect after login
• Exception handling — proper error responses for Vaadin requests
• Authorized requests — permits Vaadin framework requests (client engine, push, etc.)
• Navigation access control — enforces view access annotations

Login View

Use the built-in LoginForm component to create a login page. It provides a form with username and password fields, is compatible with password managers, and handles CSRF tokens automatically.

@Route(value = "login", autoLayout = false)
@PageTitle("Login")
@AnonymousAllowed
public class LoginView extends Main implements BeforeEnterObserver {

    private final LoginForm login;

    public LoginView() {
        login = new LoginForm();
        login.setAction("login");

        addClassNames(LumoUtility.Display.FLEX,
                LumoUtility.JustifyContent.CENTER,
                LumoUtility.AlignItems.CENTER);
        setSizeFull();
        add(login);
    }

    @Override
    public void beforeEnter(BeforeEnterEvent event) {
        if (event.getLocation()
                .getQueryParameters()
                .getParameters()
                .containsKey("error")) {
            login.setError(true);
        }
    }
}

Key points:

• autoLayout = false — prevents the login view from rendering inside the application's main layout (e.g., AppLayout with navigation menu)
• @AnonymousAllowed — required so unauthenticated users can access the page
• login.setAction("login") — makes the form POST to Spring Security's /login endpoint
• BeforeEnterObserver — checks for the ?error query parameter that Spring Security adds after a failed login attempt
• Register in SecurityConfig — configurer.loginView(LoginView.class) tells VaadinSecurityConfigurer which view is the login page

View Access Control

Control who can access each view using Jakarta and Vaadin security annotations on the view class:

Annotation	Access Level	Typical Use
@AnonymousAllowed	Anyone (no login required)	Login view, public landing page
@PermitAll	Any authenticated user	Dashboard, user profile
@RolesAllowed("ADMIN")	Users with specified role(s)	Admin panel, user management
@DenyAll	Nobody	Default when no annotation is present

@Route("public")
@AnonymousAllowed
public class PublicView extends VerticalLayout { }

@Route("dashboard")
@PermitAll
public class DashboardView extends VerticalLayout { }

@Route("admin")
@RolesAllowed("ADMIN")
public class AdminView extends VerticalLayout { }

Annotation Resolution Rules

• No annotation on a view — @DenyAll applies (access denied by default)
• Superclass annotations — inherited from the closest annotated parent class
• Child class annotated — overrides parent class annotations
• Interfaces — annotations on interfaces are not checked
• Layouts are checked independently — both the layout and the view must grant access. A view with @PermitAll inside a layout with no annotation (default @DenyAll) is inaccessible
• Override priority when multiple annotations exist — @DenyAll > @AnonymousAllowed > @RolesAllowed > @PermitAll

Role Constants

Define role names as constants to avoid typos in @RolesAllowed annotations:

public final class Roles {
    public static final String ADMIN = "ADMIN";
    public static final String USER = "USER";

    private Roles() {
    }
}

// Usage:
@RolesAllowed(Roles.ADMIN)
public class AdminView extends VerticalLayout { }

Programmatic Access Checks

Inject AuthenticationContext to check roles or get user information within a view:

@Route("settings")
@PermitAll
public class SettingsView extends VerticalLayout {

    public SettingsView(AuthenticationContext authContext) {
        authContext.getAuthenticatedUser(UserDetails.class)
                .ifPresent(user -> add(new H2("Welcome " + user.getUsername())));

        if (authContext.hasRole(Roles.ADMIN)) {
            add(new Button("Admin Settings", event -> {
                // show admin-only settings
            }));
        }
    }
}

Logout

AuthenticationContext (Recommended)

The simplest and most reliable way to log out. AuthenticationContext handles session invalidation and redirect automatically. Add a logout button to your MainLayout:

public class MainLayout extends AppLayout {

    private final transient AuthenticationContext authContext;

    public MainLayout(AuthenticationContext authContext) {
        this.authContext = authContext;

        var title = new H1("My App");
        title.addClassNames(LumoUtility.FontSize.LARGE, LumoUtility.Margin.NONE);
        var logout = new Button("Logout", event -> authContext.logout());

        var header = new HorizontalLayout(title, logout);
        header.setWidthFull();
        header.setJustifyContentMode(FlexComponent.JustifyContentMode.BETWEEN);
        header.setAlignItems(FlexComponent.Alignment.CENTER);
        header.addClassNames(LumoUtility.Padding.Horizontal.MEDIUM);

        addToNavbar(header);
    }
}

AuthenticationContext must be declared transient because it is not Serializable.

By default, logout redirects to /. To customize the post-logout redirect, specify a second parameter when registering the login view:

configurer.loginView(LoginView.class, "/goodbye");

SecurityContextLogoutHandler (Alternative)

When AuthenticationContext is not available, use SecurityContextLogoutHandler directly. The redirect must happen before the handler invalidates the session:

public void logout() {
    UI.getCurrent().getPage().setLocation("/");
    var logoutHandler = new SecurityContextLogoutHandler();
    logoutHandler.logout(
            VaadinServletRequest.getCurrent().getHttpServletRequest(),
            null, null);
}

OAuth2 / OpenID Connect

To authenticate users via an external identity provider (Google, GitHub, Keycloak, Okta, Azure AD), use Spring Security's OAuth2 client support.

Dependencies

Add the OAuth2 client starter alongside Spring Security:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-oauth2-client</artifactId>
</dependency>

Google (Common Provider)

Google is a Spring Security "common provider", so minimal configuration is needed. Only the client ID and secret are required:

spring.security.oauth2.client.registration.google.client-id=${GOOGLE_CLIENT_ID}
spring.security.oauth2.client.registration.google.client-secret=${GOOGLE_CLIENT_SECRET}
spring.security.oauth2.client.registration.google.scope=openid,profile,email

Keycloak (Custom Provider)

Providers that are not built into Spring Security require full configuration including the issuer URI:

spring.security.oauth2.client.registration.keycloak.provider=keycloak
spring.security.oauth2.client.registration.keycloak.client-id=my-client-id
spring.security.oauth2.client.registration.keycloak.client-secret=${KEYCLOAK_CLIENT_SECRET}
spring.security.oauth2.client.registration.keycloak.authorization-grant-type=authorization_code
spring.security.oauth2.client.registration.keycloak.scope=openid,profile

spring.security.oauth2.client.provider.keycloak.issuer-uri=http://keycloak.local:8180/realms/my-app

SecurityConfig for OAuth2

Replace loginView() with oauth2LoginPage(), pointing to the provider's authorization URI:

@EnableWebSecurity
@Configuration
public class SecurityConfig {

    @Bean
    SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http.with(VaadinSecurityConfigurer.vaadin(), configurer -> {
            configurer.oauth2LoginPage(
                    "/oauth2/authorization/google",
                    "{baseUrl}");
        });
        return http.build();
    }
}

The {baseUrl} template variable resolves to the application's base URL and is used as the post-logout redirect URI. Other supported variables: {baseScheme}, {baseHost}, {basePort}, {basePath}.

When using OAuth2, no LoginView class is needed — the identity provider handles the login UI. Users are redirected to the provider's login page and back to the application after authentication.

OAuth2 Logout

For OAuth2 applications, use AuthenticationContext.logout() the same way as with form login. The VaadinSecurityConfigurer handles the OAuth2-specific logout flow.

Other Providers

The same pattern works for GitHub, Okta, and Azure AD. The only differences are:

• application.properties — the registration and provider keys change per provider
• oauth2LoginPage() URL — use /oauth2/authorization/{registrationId} where {registrationId} matches the key in application.properties
• Common providers (Google, GitHub, Facebook, Okta) need only client-id, client-secret, and scope
• Custom providers (Keycloak, Azure AD) also need issuer-uri and authorization-grant-type

Best Practices

1. Never hard-code credentials — use environment variables or a secrets manager. The UserDetailsManager with {noop} passwords is for development only.
2. Annotate every view and layout — views without an access annotation default to @DenyAll. Layouts are checked independently; both must grant access.
3. Use AuthenticationContext for logout and user info — it integrates with Spring Security and handles session cleanup correctly. Declare the field transient.
4. Use autoLayout = false on the login view — the login view should not render inside the application's main layout.
5. Prefer VaadinSecurityConfigurer over manual Spring Security config — it handles CSRF, logout, request caching, and exception handling for Vaadin automatically.
6. Externalize OAuth2 credentials — use application.properties with environment variable references (${GOOGLE_CLIENT_SECRET}) or Spring profiles.
7. Define role constants — create a Roles class with public static final String fields to avoid typos in @RolesAllowed annotations.
8. Leverage Vaadin's server-side security model — UI state lives on the server, so attackers cannot tamper with it from the browser. Combined with annotation-based access control, this provides defense in depth.

Anti-Patterns

1. Forgetting autoLayout = false on the login view — the login form renders inside the app shell with the navigation menu, which is confusing and may cause access control issues.
2. Forgetting to annotate the layout — a view marked @PermitAll inside a layout with no annotation (default @DenyAll) is inaccessible. Both must independently grant access.
3. Using @Secured or @PreAuthorize on views — these Spring Security annotations are not supported on Vaadin views. Use @AnonymousAllowed, @PermitAll, @RolesAllowed, or @DenyAll.
4. Hard-coding passwords in SecurityConfig — in-memory {noop} passwords are for prototyping only. Production applications must use JDBC, LDAP, or OAuth2 authentication.
5. Calling SecurityContextLogoutHandler without redirecting first — the logout handler invalidates the session, so UI.getCurrent().getPage().setLocation() must happen before the handler call. Prefer AuthenticationContext.logout() which handles this correctly.
6. Mixing URL-pattern security and annotation-based security for the same views — this leads to confusing, hard-to-debug access rules. Choose one approach.

Detailed Reference

For a quick-reference cheatsheet of security annotations, OAuth2 provider configurations, login view checklist, and SecurityConfig templates, see references/security-patterns.md.