diff --git a/core/modules/node/src/Form/DeleteMultiple.php b/core/modules/node/src/Form/DeleteMultiple.php
index 7b2aced..a5686dc 100644
--- a/core/modules/node/src/Form/DeleteMultiple.php
+++ b/core/modules/node/src/Form/DeleteMultiple.php
@@ -13,8 +13,8 @@
 use Drupal\Component\Utility\String;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\user\TempStoreFactory;
-use Symfony\Component\HttpFoundation\RedirectResponse;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 
 /**
  * Provides a node deletion confirmation form.
@@ -99,7 +99,7 @@ public function getConfirmText() {
   public function buildForm(array $form, FormStateInterface $form_state) {
     $this->nodes = $this->tempStoreFactory->get('node_multiple_delete_confirm')->get(\Drupal::currentUser()->id());
     if (empty($this->nodes)) {
-      return new RedirectResponse($this->getCancelUrl()->setAbsolute()->toString());
+      throw new AccessDeniedHttpException();
     }
 
     $form['nodes'] = array(
diff --git a/core/modules/node/src/Tests/NodeAdminTest.php b/core/modules/node/src/Tests/NodeAdminTest.php
index d88d7db..37ce473 100644
--- a/core/modules/node/src/Tests/NodeAdminTest.php
+++ b/core/modules/node/src/Tests/NodeAdminTest.php
@@ -164,5 +164,11 @@ function testContentAdminPages() {
       $this->assertLinkByHref('node/' . $node->id() . '/edit');
       $this->assertLinkByHref('node/' . $node->id() . '/delete');
     }
+
+    $this->drupalPostForm(NULL, [], 'Apply');
+    $this->assertRaw('No content selected');
+    $this->drupalGet('admin/content/node/delete');
+    $this->assertResponse(403);
   }
+
 }
diff --git a/core/modules/system/src/Form/ModulesListConfirmForm.php b/core/modules/system/src/Form/ModulesListConfirmForm.php
index c04a030..cd8825c 100644
--- a/core/modules/system/src/Form/ModulesListConfirmForm.php
+++ b/core/modules/system/src/Form/ModulesListConfirmForm.php
@@ -13,6 +13,7 @@
 use Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface;
 use Drupal\Core\Url;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 
 /**
  * Builds a confirmation form for enabling modules with dependencies.
@@ -107,7 +108,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
 
     // Redirect to the modules list page if the key value store is empty.
     if (!$this->modules) {
-      return $this->redirect('system.modules_list');
+      throw new AccessDeniedHttpException();
     }
 
     $items = array();
diff --git a/core/modules/system/src/Form/ModulesUninstallConfirmForm.php b/core/modules/system/src/Form/ModulesUninstallConfirmForm.php
index 5a0e0fe..8b868a9 100644
--- a/core/modules/system/src/Form/ModulesUninstallConfirmForm.php
+++ b/core/modules/system/src/Form/ModulesUninstallConfirmForm.php
@@ -12,10 +12,10 @@
 use Drupal\Core\Form\ConfirmFormBase;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Url;
-use Symfony\Component\HttpFoundation\RedirectResponse;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 
 /**
  * Builds a confirmation form to uninstall selected modules.
@@ -133,7 +133,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
 
     // Prevent this page from showing when the module list is empty.
     if (empty($this->modules)) {
-      return new RedirectResponse('/admin/modules/uninstall');
+      throw new AccessDeniedHttpException();
     }
 
     $data = system_rebuild_module_data();
diff --git a/core/modules/system/src/Form/ModulesUninstallForm.php b/core/modules/system/src/Form/ModulesUninstallForm.php
index 4285956..208b352 100644
--- a/core/modules/system/src/Form/ModulesUninstallForm.php
+++ b/core/modules/system/src/Form/ModulesUninstallForm.php
@@ -152,8 +152,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
   public function validateForm(array &$form, FormStateInterface $form_state) {
     // Form submitted, but no modules selected.
     if (!array_filter($form_state->getValue('uninstall'))) {
-      drupal_set_message($this->t('No modules selected.'), 'error');
-      $form_state->setRedirect('system.modules_uninstall');
+      $form_state->setErrorByName('', $this->t('No modules selected.'));
     }
   }
 
diff --git a/core/modules/system/src/Tests/Module/UninstallTest.php b/core/modules/system/src/Tests/Module/UninstallTest.php
index e57bff0..3926c8e 100644
--- a/core/modules/system/src/Tests/Module/UninstallTest.php
+++ b/core/modules/system/src/Tests/Module/UninstallTest.php
@@ -45,6 +45,12 @@ function testUninstallPage() {
     $this->drupalGet('admin/modules/uninstall');
     $this->assertTitle(t('Uninstall') . ' | Drupal');
 
+    // Attempt to uninstall no modules.
+    $this->drupalPostForm(NULL, [], 'Uninstall');
+    $this->assertResponse(200);
+    $this->drupalGet('admin/modules/uninstall/confirm');
+    $this->assertResponse(403);
+
     // Uninstall module_test.
     $edit = array();
     $edit['uninstall[module_test]'] = TRUE;
diff --git a/core/modules/user/src/RegisterForm.php b/core/modules/user/src/RegisterForm.php
index be73f39..326adcf 100644
--- a/core/modules/user/src/RegisterForm.php
+++ b/core/modules/user/src/RegisterForm.php
@@ -42,11 +42,6 @@ public function form(array $form, FormStateInterface $form_state) {
       '#value' => $admin,
     );
 
-    // If we aren't admin but already logged on, go to the user page instead.
-    if (!$admin && $user->isAuthenticated()) {
-      return new RedirectResponse($this->url('entity.user.canonical', ['user' => \Drupal::currentUser()->id()], array('absolute' => TRUE)));
-    }
-
     $form['#attached']['library'][] = 'core/drupal.form';
 
     // For non-admin users, populate the form fields using data from the