diff --git a/core/core.services.yml b/core/core.services.yml
index 4d8cf79..aadc0ed 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -1044,6 +1044,11 @@ services:
   session.attribute_bag:
     class: Symfony\Component\HttpFoundation\Session\Attribute\AttributeBag
     public: false
+  session.subrequest_session_subscrber:
+    class: Drupal\Core\EventSubscriber\SubRequestSessionSubscriber
+    public: false
+    tags:
+      - { name: event_subscriber }
   session_manager:
     class: Drupal\Core\Session\SessionManager
     arguments: ['@request_stack', '@database', '@session_manager.metadata_bag', '@settings']
diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index 75672f1..f75820e 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -439,6 +439,7 @@ function install_begin_request($class_loader, &$install_state) {
   }
 
   // Load all modules and perform request related initialization.
+  // @see \Drupal\Core\DrupalKernel::prepareLegacyRequest
   $kernel->preHandle($request);
   $request->attributes->set(RouteObjectInterface::ROUTE_OBJECT, new Route('<none>'));
   $request->attributes->set(RouteObjectInterface::ROUTE_NAME, '<none>');
diff --git a/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php
index 154c697..389cc19 100644
--- a/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php
@@ -111,11 +111,6 @@ protected function makeSubrequest(GetResponseForExceptionEvent $event, $path, $s
         // Persist the 'exception' attribute to the subrequest.
         $sub_request->attributes->set('exception', $request->attributes->get('exception'));
 
-        // Carry over the session to the subrequest.
-        if ($session = $request->getSession()) {
-          $sub_request->setSession($session);
-        }
-
         $response = $this->httpKernel->handle($sub_request, HttpKernelInterface::SUB_REQUEST);
         $response->setStatusCode($status_code);
         $event->setResponse($response);
diff --git a/core/lib/Drupal/Core/EventSubscriber/SubRequestSessionSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/SubRequestSessionSubscriber.php
new file mode 100644
index 0000000..7464618
--- /dev/null
+++ b/core/lib/Drupal/Core/EventSubscriber/SubRequestSessionSubscriber.php
@@ -0,0 +1,66 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\EventSubscriber\SubRequestSessionSubscriber.
+ */
+
+namespace Drupal\Core\EventSubscriber;
+
+use Drupal\Core\Authentication\AuthenticationProviderInterface;
+use Symfony\Component\HttpFoundation\RequestStack;
+use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
+use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Sub-request subscriber.
+ *
+ * Hand session down to sub-requests.
+ */
+class SubRequestSessionSubscriber implements EventSubscriberInterface {
+
+  /**
+   * Current request stack.
+   *
+   * @var \Symfony\Component\HttpFoundation\RequestStack
+   */
+  protected $requestStack;
+
+  /**
+   * Constructs a new SubRequestSessionSubscriber object.
+   *
+   * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
+   *   The request stack.
+   */
+  public function __construct(RequestStack $request_stack) {
+    $this->requestStack = $request_stack;
+  }
+
+  /**
+   * If the request is a sub-request, ensures session is copied from master.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event
+   *   The request event.
+   */
+  public function onRequest(GetResponseEvent $event) {
+    if ($event->getRequestType() == HttpKernelInterface::SUB_REQUEST) {
+      $parent = $this->requestStack->getParentRequest();
+      if ($parent->hasSession()) {
+        $request = $event->getRequest();
+        $request->setSession($parent->getSession());
+      }
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    $events[KernelEvents::REQUEST][] = ['onRequest', 50];
+    return $events;
+  }
+}
diff --git a/core/modules/comment/src/Controller/CommentController.php b/core/modules/comment/src/Controller/CommentController.php
index b2846be..4af3f05 100644
--- a/core/modules/comment/src/Controller/CommentController.php
+++ b/core/modules/comment/src/Controller/CommentController.php
@@ -130,10 +130,6 @@ public function commentPermalink(Request $request, CommentInterface $comment) {
       // @todo: Cleaner sub request handling.
       $redirect_request = Request::create($entity->getSystemPath(), 'GET', $request->query->all(), $request->cookies->all(), array(), $request->server->all());
       $redirect_request->query->set('page', $page);
-      // Carry over the session to the subrequest.
-      if ($session = $request->getSession()) {
-        $redirect_request->setSession($session);
-      }
       // @todo: Convert the pager to use the request object.
       $request->query->set('page', $page);
       return $this->httpKernel->handle($redirect_request, HttpKernelInterface::SUB_REQUEST);