I've implemented a sample spring boot application with vaadin-flow. I implemented an in-memory authorization with two roles (User, Admin). When login at the first time the system ask for the credentials as expected. I requested "/my/logout" url to logout, After that I can still access restricted content without providing the user credentials (user login is not prompted). Following is my web security config
http.csrf().disable().
authorizeRequests()
.anyRequest().authenticated()
.antMatchers("/VAADIN/**", "/PUSH/**", "/UIDL/**", "/login", "/login/**", "/error/**", "/accessDenied/**", "/vaadinServlet/**").permitAll()
.and().httpBasic()
.and().logout().logoutUrl("/my/logout")
.permitAll();