diff --git a/src/main/java/org/wise/portal/spring/impl/WebSecurityConfig.java b/src/main/java/org/wise/portal/spring/impl/WebSecurityConfig.java
index b608d1272..7e215778a 100644
--- a/src/main/java/org/wise/portal/spring/impl/WebSecurityConfig.java
+++ b/src/main/java/org/wise/portal/spring/impl/WebSecurityConfig.java
@@ -85,14 +85,42 @@ protected void configure(HttpSecurity http) throws Exception {
         .addFilterAfter(googleOpenIdConnectFilter(), OAuth2ClientContextFilter.class)
         .addFilterAfter(microsoftOpenIdConnectFilter(), OAuth2ClientContextFilter.class)
         .addFilterAfter(authenticationProcessingFilter(), GoogleOpenIdConnectFilter.class)
-        .authorizeRequests().antMatchers("/api/login/impersonate")
-        .hasAnyRole("ADMINISTRATOR", "RESEARCHER").antMatchers("/admin/**")
-        .hasAnyRole("ADMINISTRATOR", "RESEARCHER").antMatchers("/author/**").hasAnyRole("TEACHER")
+        .authorizeRequests()
+        // Static assets served by the resource handlers configured in WebConfig are public
+        // content (portal scripts, themes and translations, the runtime engine, project
+        // files and project icons). They must stay reachable without signing in, now that
+        // unmatched requests are denied by default, otherwise the login and public preview
+        // pages would fail to load their assets. Student uploaded files are intentionally
+        // excluded so they continue to require authentication.
+        .antMatchers("/pages/resources/**", "/portal/javascript/**", "/portal/themes/**",
+            "/portal/translate/**", "/vle/**", "/curriculum/**", "/projectIcons/**").permitAll()
+        .antMatchers("/api/login/impersonate").hasAnyRole("ADMINISTRATOR", "RESEARCHER")
+        .antMatchers("/admin/**").hasAnyRole("ADMINISTRATOR", "RESEARCHER")
+        .antMatchers("/author/**").hasAnyRole("TEACHER")
         .antMatchers("/project/notifyAuthor*/**").hasAnyRole("TEACHER")
-        .antMatchers("/student/account/info").hasAnyRole("TEACHER").antMatchers("/student/**")
-        .hasAnyRole("STUDENT").antMatchers("/studentStatus").hasAnyRole("TEACHER", "STUDENT")
-        .antMatchers("/teacher/**").hasAnyRole("TEACHER").antMatchers("/sso/discourse")
-        .hasAnyRole("TEACHER", "STUDENT").antMatchers("/").permitAll();
+        .antMatchers("/student/account/info").hasAnyRole("TEACHER")
+        .antMatchers("/student/**").hasAnyRole("STUDENT")
+        .antMatchers("/studentStatus").hasAnyRole("TEACHER", "STUDENT")
+        .antMatchers("/teacher/**").hasAnyRole("TEACHER")
+        .antMatchers("/sso/discourse").hasAnyRole("TEACHER", "STUDENT")
+        // Endpoints that must stay reachable without authentication: sign-in and its
+        // OAuth callbacks, account registration, account and password recovery, the
+        // contact form, the public home, news, library and preview content, and the
+        // application bootstrap configuration. Every request that does not match a rule
+        // above falls through to the final rule and now requires authentication, rather
+        // than being permitted by default.
+        .antMatchers("/", "/login", "/login/**", "/errors/**", "/run-survey/**",
+            "/previewproject.html").permitAll()
+        .antMatchers("/api/j_acegi_security_check", "/api/google-login", "/api/microsoft-login",
+            "/api/logout").permitAll()
+        .antMatchers("/api/student/register", "/api/student/register/questions",
+            "/api/teacher/register", "/api/contact").permitAll()
+        .antMatchers("/api/student/forgot/**", "/api/teacher/forgot/**").permitAll()
+        .antMatchers("/api/user/config", "/api/user/info", "/api/user/languages",
+            "/api/announcement", "/api/news", "/api/project/library", "/api/project/community",
+            "/api/config/vle", "/api/config/preview/**", "/api/run/info", "/api/runInfo",
+            "/api/session/renew", "/api/google-user/check-user-exists").permitAll()
+        .anyRequest().authenticated();
     http.formLogin().loginPage("/login").permitAll();
     http.logout().addLogoutHandler(wiseLogoutHandler())
         .logoutRequestMatcher(new AntPathRequestMatcher("/api/logout"));