diff --git a/flow-client/src/main/resources/META-INF/resources/frontend/form/index.ts b/flow-client/src/main/resources/META-INF/resources/frontend/form/index.ts
index 9cd7af6200f..f0695723fc5 100644
--- a/flow-client/src/main/resources/META-INF/resources/frontend/form/index.ts
+++ b/flow-client/src/main/resources/META-INF/resources/frontend/form/index.ts
@@ -9,5 +9,5 @@ $wnd.Vaadin = $wnd.Vaadin || {};
 $wnd.Vaadin.registrations = $wnd.Vaadin.registrations || [];
 $wnd.Vaadin.registrations.push({
   is: '@vaadin/form',
-  version: /* updated-by-script */ '5.0-SNAPSHOT'
+  version: /* updated-by-script */ '6.0-SNAPSHOT'
 });
diff --git a/flow-server/src/main/java/com/vaadin/flow/server/connect/auth/VaadinConnectAccessChecker.java b/flow-server/src/main/java/com/vaadin/flow/server/connect/auth/VaadinConnectAccessChecker.java
index 38b1f01ca36..c6faaa03e82 100644
--- a/flow-server/src/main/java/com/vaadin/flow/server/connect/auth/VaadinConnectAccessChecker.java
+++ b/flow-server/src/main/java/com/vaadin/flow/server/connect/auth/VaadinConnectAccessChecker.java
@@ -16,18 +16,20 @@
 
 package com.vaadin.flow.server.connect.auth;
 
-import com.vaadin.flow.server.VaadinService;
-
 import javax.annotation.security.DenyAll;
 import javax.annotation.security.PermitAll;
 import javax.annotation.security.RolesAllowed;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpSession;
-
 import java.lang.reflect.AnnotatedElement;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.vaadin.flow.server.VaadinService;
+
 /**
  * Component used for checking role-based ACL in Vaadin Endpoints.
  * <p>
@@ -145,8 +147,26 @@ private boolean requestForbidden(HttpServletRequest request) {
             return false;
         }
 
-        String csrfTokenInSession = (String) session.getAttribute(VaadinService.getCsrfTokenAttributeName());
-        return csrfTokenInSession == null || !csrfTokenInSession.equals(request.getHeader("X-CSRF-Token"));
+        String csrfTokenInSession = (String) session
+                .getAttribute(VaadinService.getCsrfTokenAttributeName());
+        if (csrfTokenInSession == null) {
+            if (getLogger().isInfoEnabled()) {
+                getLogger().info(
+                        "Unable to verify CSRF token for endpoint request, got null token in session");
+            }
+
+            return true;
+        }
+
+        if (!csrfTokenInSession.equals(request.getHeader("X-CSRF-Token"))) {
+            if (getLogger().isInfoEnabled()) {
+                getLogger().info("Invalid CSRF token in endpoint request");
+            }
+
+            return true;
+        }
+
+        return false;
     }
 
     private boolean entityForbidden(AnnotatedElement entity,
@@ -187,4 +207,8 @@ private boolean hasSecurityAnnotation(Method method) {
     public void enableCsrf(boolean xsrfProtectionEnabled) {
         this.xsrfProtectionEnabled = xsrfProtectionEnabled;
     }
+
+    private static Logger getLogger() {
+        return LoggerFactory.getLogger(VaadinConnectAccessChecker.class);
+    }
 }
diff --git a/flow-tests/test-ccdm-flow-navigation/src/main/java/com/vaadin/flow/navigate/SessionView.java b/flow-tests/test-ccdm-flow-navigation/src/main/java/com/vaadin/flow/navigate/SessionView.java
new file mode 100644
index 00000000000..9682ab84b0f
--- /dev/null
+++ b/flow-tests/test-ccdm-flow-navigation/src/main/java/com/vaadin/flow/navigate/SessionView.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2000-2020 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.flow.navigate;
+
+import com.vaadin.flow.component.Text;
+import com.vaadin.flow.component.html.Div;
+import com.vaadin.flow.component.html.NativeButton;
+import com.vaadin.flow.router.PageTitle;
+import com.vaadin.flow.router.Route;
+import com.vaadin.flow.server.VaadinSession;
+
+@Route(value="session")
+@PageTitle("Session")
+public class SessionView extends Div {
+    public SessionView() {
+        super();
+
+        add(new Text("Session view"));
+        setId("sessionView");
+
+        NativeButton invalidateSession = new NativeButton("Invalidate session",
+                event -> VaadinSession.getCurrent().getSession().invalidate());
+        invalidateSession.setId("invalidateSession");
+        add(invalidateSession);
+    }
+}
diff --git a/flow-tests/test-ccdm-flow-navigation/src/test/java/com/vaadin/flow/navigate/SessionViewIT.java b/flow-tests/test-ccdm-flow-navigation/src/test/java/com/vaadin/flow/navigate/SessionViewIT.java
new file mode 100644
index 00000000000..a65b12b4458
--- /dev/null
+++ b/flow-tests/test-ccdm-flow-navigation/src/test/java/com/vaadin/flow/navigate/SessionViewIT.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2000-2020 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.flow.navigate;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.vaadin.flow.testutil.ChromeBrowserTest;
+
+public class SessionViewIT extends ChromeBrowserTest {
+    @Test
+    public void indexHtmlRequestHandler_csrfToken_should_update_after_invalidateSession() {
+        open();
+
+        String originalCsrfToken = executeScript(
+                "return Vaadin.TypeScript.csrfToken;").toString();
+
+        $("button").attribute("id", "invalidateSession").waitForFirst().click();
+
+        open();
+        String csrfToken = executeScript("return Vaadin.TypeScript.csrfToken;")
+                .toString();
+
+        Assert.assertNotEquals(
+                "CSRF token should update when session is invalidated",
+                originalCsrfToken, csrfToken);
+    }
+
+    @Override
+    protected String getTestPath() {
+        return "/session";
+    }
+}