diff --git a/core/modules/comment/src/CommentForm.php b/core/modules/comment/src/CommentForm.php
index 0f9c7dbd6c..48cd1085d9 100644
--- a/core/modules/comment/src/CommentForm.php
+++ b/core/modules/comment/src/CommentForm.php
@@ -7,6 +7,7 @@
 use Drupal\Component\Utility\Html;
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Datetime\DrupalDateTime;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Entity\ContentEntityForm;
 use Drupal\Core\Entity\EntityConstraintViolationListInterface;
 use Drupal\Core\Entity\EntityFieldManagerInterface;
@@ -15,6 +16,7 @@
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Link;
 use Drupal\Core\Render\RendererInterface;
+use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\Core\Url;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -47,6 +49,20 @@ class CommentForm extends ContentEntityForm {
    */
   protected $entityFieldManager;
 
+  /**
+   * The commented entity obtained from route.
+   *
+   * @var \Drupal\node\EntityInterface
+   */
+  protected $commentedEntity;
+
+  /**
+   * The entity type manager.
+   *
+   * @var \Drupal\node\EntityInterface
+   */
+  protected $entityTypeManager;
+
   /**
    * {@inheritdoc}
    */
@@ -57,7 +73,9 @@ public static function create(ContainerInterface $container) {
       $container->get('renderer'),
       $container->get('entity_type.bundle.info'),
       $container->get('datetime.time'),
-      $container->get('entity_field.manager')
+      $container->get('entity_field.manager'),
+      $container->get('current_route_match'),
+      $container->get('entity_type.manager')
     );
   }
 
@@ -76,12 +94,32 @@ public static function create(ContainerInterface $container) {
    *   The time service.
    * @param \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager
    *   The entity field manager service.
+   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
+   *   The route match.
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
+   *   The entity type manager.
    */
-  public function __construct(EntityRepositoryInterface $entity_repository, AccountInterface $current_user, RendererInterface $renderer, EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, TimeInterface $time = NULL, EntityFieldManagerInterface $entity_field_manager = NULL) {
+  public function __construct(EntityRepositoryInterface $entity_repository, AccountInterface $current_user, RendererInterface $renderer, EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, TimeInterface $time = NULL, EntityFieldManagerInterface $entity_field_manager = NULL, RouteMatchInterface $route_match, EntityTypeManagerInterface $entity_type_manager) {
     parent::__construct($entity_repository, $entity_type_bundle_info, $time);
     $this->currentUser = $current_user;
     $this->renderer = $renderer;
     $this->entityFieldManager = $entity_field_manager ?: \Drupal::service('entity_field.manager');
+    $this->entityTypeManager = $entity_type_manager ?: \Drupal::service('entity_type_manager');
+
+    // Get node entity from route match.
+    $parameters = $route_match->getParameters();
+    if ($parameters->has('node')) {
+      $this->commentedEntity = $parameters->get('node');
+    }
+    elseif ($parameters->has('entity')) {
+      $this->commentedEntity = $parameters->get('entity');
+    }
+    elseif ($parameters->has('comment')) {
+      $comment = $parameters->get('comment');
+      $this->commentedEntity = $this->entityTypeManager
+        ->getStorage($comment->getCommentedEntityTypeId())
+        ->load($comment->getCommentedEntityId());
+    }
   }
 
   /**
@@ -119,8 +157,15 @@ public function form(array $form, FormStateInterface $form_state) {
 
     // If not replying to a comment, use our dedicated page callback for new
     // Comments on entities.
-    if (!$comment->id() && !$comment->hasParentComment()) {
-      $form['#action'] = Url::fromRoute('comment.reply', ['entity_type' => $entity->getEntityTypeId(), 'entity' => $entity->id(), 'field_name' => $field_name])->toString();
+    if (isset($this->commentedEntity) &&
+             $this->commentedEntity->getEntityTypeId() == $entity->getEntityTypeId() &&
+             $this->commentedEntity->id() == $entity->id() && !$comment->id() &&
+             !$comment->hasParentComment()) {
+      $form['#action'] = Url::fromRoute('comment.reply', [
+        'entity_type' => $entity->getEntityTypeId(),
+        'entity' => $entity->id(),
+        'field_name' => $field_name,
+      ])->toString();
     }
 
     $comment_preview = $form_state->get('comment_preview');
@@ -411,7 +456,11 @@ public function save(array $form, FormStateInterface $form_state) {
       $this->messenger()->addError($this->t('Comment: unauthorized comment submitted or comment submitted to a closed post %subject.', ['%subject' => $comment->getSubject()]));
       // Redirect the user to the entity they are commenting on.
     }
-    $form_state->setRedirectUrl($uri);
+    if (isset($this->commentedEntity) &&
+      $this->commentedEntity->getEntityTypeId() == $entity->getEntityTypeId() &&
+      $this->commentedEntity->id() == $entity->id() && $uri->access()) {
+      $form_state->setRedirectUrl($uri);
+    }
   }
 
 }
diff --git a/core/modules/comment/tests/src/Functional/CommentTestBase.php b/core/modules/comment/tests/src/Functional/CommentTestBase.php
index 1007a7983a..9247c33313 100644
--- a/core/modules/comment/tests/src/Functional/CommentTestBase.php
+++ b/core/modules/comment/tests/src/Functional/CommentTestBase.php
@@ -183,6 +183,19 @@ public function postComment($entity, $comment, $subject = '', $contact = NULL, $
       \Drupal::entityTypeManager()->getStorage('comment')->resetCache([$match[1]]);
       return Comment::load($match[1]);
     }
+    else {
+      $cids = \Drupal::entityQuery('comment')
+        ->condition('entity_id', $entity->id())
+        ->condition('field_name', $field_name)
+        ->sort('cid', 'DESC')
+        ->range(0, 1)
+        ->execute();
+      if (!empty($cids)) {
+        $cid = reset($cids);
+        \Drupal::entityTypeManager()->getStorage('comment')->resetCache([$cid]);
+        return Comment::load($cid);
+      }
+    }
   }
 
   /**