diff --git a/core/lib/Drupal/Core/EventSubscriber/CustomPageExceptionHtmlSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/CustomPageExceptionHtmlSubscriber.php
index 0422bf0..c393a34 100644
--- a/core/lib/Drupal/Core/EventSubscriber/CustomPageExceptionHtmlSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/CustomPageExceptionHtmlSubscriber.php
@@ -63,7 +63,7 @@ protected static function getPriority() {
    */
   public function on403(GetResponseForExceptionEvent $event) {
     $path = $this->aliasManager->getPathByAlias($this->configFactory->get('system.site')->get('page.403'));
-    $this->makeSubrequest($event, $event->getRequest()->getBasePath() . '/' . $path, Response::HTTP_FORBIDDEN);
+    $this->makeSubrequest($event, $path, Response::HTTP_FORBIDDEN);
   }
 
   /**
@@ -71,7 +71,7 @@ public function on403(GetResponseForExceptionEvent $event) {
    */
   public function on404(GetResponseForExceptionEvent $event) {
     $path = $this->aliasManager->getPathByAlias($this->configFactory->get('system.site')->get('page.404'));
-    $this->makeSubrequest($event, $event->getRequest()->getBasePath() . '/' . $path, Response::HTTP_NOT_FOUND);
+    $this->makeSubrequest($event, $path, Response::HTTP_NOT_FOUND);
   }
 
 }
diff --git a/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php
index d6782b2..7d71d8c 100644
--- a/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php
@@ -89,21 +89,25 @@ public function on404(GetResponseForExceptionEvent $event) {
    * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
    *   The event to process
    * @param string $url
-   *   The url to which to make a subrequest for this error message.
+   *   The path/url to which to make a subrequest for this error message.
    * @param int $status_code
    *   The status code for the error being handled.
    */
   protected function makeSubrequest(GetResponseForExceptionEvent $event, $url, $status_code) {
     $request = $event->getRequest();
 
+    if (!($url && $url[0] == '/')) {
+      $url = $request->getBasePath() . '/' . $url;
+    }
+
     $current_url = $request->getBasePath() . $request->getPathInfo();
 
     if ($url != $request->getBasePath() . '/' && $url != $current_url) {
       if ($request->getMethod() === 'POST') {
-        $sub_request = Request::create($url, 'POST', drupal_get_destination() + ['_exception_statuscode' => $status_code] + $request->request->all(), $request->cookies->all(), [], $request->server->all());
+        $sub_request = Request::create($url, 'POST', $this->drupalGetDestination() + ['_exception_statuscode' => $status_code] + $request->request->all(), $request->cookies->all(), [], $request->server->all());
       }
       else {
-        $sub_request = Request::create($url, 'GET', $request->query->all() + drupal_get_destination() + ['_exception_statuscode' => $status_code], $request->cookies->all(), [], $request->server->all());
+        $sub_request = Request::create($url, 'GET', $request->query->all() + $this->drupalGetDestination() + ['_exception_statuscode' => $status_code], $request->cookies->all(), [], $request->server->all());
       }
 
       try {
@@ -124,4 +128,11 @@ protected function makeSubrequest(GetResponseForExceptionEvent $event, $url, $st
     }
   }
 
+  /**
+   * Wraps drupal_get_destination().
+   */
+  protected function drupalGetDestination() {
+    return drupal_get_destination();
+  }
+
 }
diff --git a/core/lib/Drupal/Core/RouteProcessor/RouteProcessorCurrent.php b/core/lib/Drupal/Core/RouteProcessor/RouteProcessorCurrent.php
index e4bc705..7a0023f 100644
--- a/core/lib/Drupal/Core/RouteProcessor/RouteProcessorCurrent.php
+++ b/core/lib/Drupal/Core/RouteProcessor/RouteProcessorCurrent.php
@@ -36,12 +36,18 @@ public function __construct(RouteMatchInterface $route_match) {
    * {@inheritdoc}
    */
   public function processOutbound($route_name, Route $route, array &$parameters) {
-    if (($route_name === '<current>') && ($current_route = $this->routeMatch->getRouteObject())) {
-      $route->setPath($current_route->getPath());
-      $route->setRequirements($current_route->getRequirements());
-      $route->setOptions($current_route->getOptions());
-      $route->setDefaults($current_route->getDefaults());
-      $parameters = array_merge($parameters, $this->routeMatch->getRawParameters()->all());
+    if ($route_name === '<current>') {
+      if ($current_route = $this->routeMatch->getRouteObject()) {
+        $route->setPath($current_route->getPath());
+        $route->setRequirements($current_route->getRequirements());
+        $route->setOptions($current_route->getOptions());
+        $route->setDefaults($current_route->getDefaults());
+        $parameters = array_merge($parameters, $this->routeMatch->getRawParameters()->all());
+      }
+      else {
+        // If we have no current route match available, point to the frontpage.
+        $route->setPath('');
+      }
     }
   }
 
diff --git a/core/modules/system/src/Tests/RouteProcessor/RouteProcessorCurrentIntegrationTest.php b/core/modules/system/src/Tests/RouteProcessor/RouteProcessorCurrentIntegrationTest.php
index d21d834..bb66f59 100644
--- a/core/modules/system/src/Tests/RouteProcessor/RouteProcessorCurrentIntegrationTest.php
+++ b/core/modules/system/src/Tests/RouteProcessor/RouteProcessorCurrentIntegrationTest.php
@@ -96,6 +96,19 @@ public function testProcessOutbound() {
     $request_stack->push($request);
     $request_context->fromRequest($request);
     $this->assertEqual('/node/add', \Drupal::url('<current>'));
+
+    // Test request without a found route. This happens for example on an
+    // not found exception page.
+    $server = [
+      'SCRIPT_NAME' => '/index.php',
+      'SCRIPT_FILENAME' => \Drupal::root() . '/index.php',
+      'SERVER_NAME' => 'http://www.example.com',
+    ];
+    $request = Request::create('/invalid-path', 'GET', [], [], [], $server);
+
+    $request_stack->push($request);
+    $request_context->fromRequest($request);
+    $this->assertEqual('/', \Drupal::url('<current>'));
   }
 
 }
diff --git a/core/tests/Drupal/Tests/Core/EventSubscriber/CustomPageExceptionHtmlSubscriberTest.php b/core/tests/Drupal/Tests/Core/EventSubscriber/CustomPageExceptionHtmlSubscriberTest.php
index 1de4249..5b73c85 100644
--- a/core/tests/Drupal/Tests/Core/EventSubscriber/CustomPageExceptionHtmlSubscriberTest.php
+++ b/core/tests/Drupal/Tests/Core/EventSubscriber/CustomPageExceptionHtmlSubscriberTest.php
@@ -60,7 +60,7 @@ class CustomPageExceptionHtmlSubscriberTest extends UnitTestCase {
   /**
    * The tested custom page exception subscriber.
    *
-   * @var \Drupal\Core\EventSubscriber\CustomPageExceptionHtmlSubscriber
+   * @var \Drupal\Core\EventSubscriber\CustomPageExceptionHtmlSubscriber|\Drupal\Tests\Core\EventSubscriber\TestCustomPageExceptionHtmlSubscriber
    */
   protected $customPageSubscriber;
 
@@ -73,7 +73,7 @@ protected function setUp() {
     $this->aliasManager = $this->getMock('Drupal\Core\Path\AliasManagerInterface');
     $this->kernel = $this->getMock('Symfony\Component\HttpKernel\HttpKernelInterface');
     $this->logger = $this->getMock('Psr\Log\LoggerInterface');
-    $this->customPageSubscriber = new CustomPageExceptionHtmlSubscriber($this->configFactory, $this->aliasManager, $this->kernel, $this->logger);
+    $this->customPageSubscriber = new TestCustomPageExceptionHtmlSubscriber($this->configFactory, $this->aliasManager, $this->kernel, $this->logger);
 
     // You can't create an exception in PHP without throwing it. Store the
     // current error_log, and disable it temporarily.
@@ -124,7 +124,6 @@ public function testHandleWithGetRequest() {
     $this->setupStubAliasManager();
 
     $request = Request::create('/test', 'GET', array('name' => 'druplicon', 'pass' => '12345'));
-    $request->attributes->set('_system_path', 'test');
 
     $this->kernel->expects($this->once())->method('handle')->will($this->returnCallback(function (Request $request) {
       return new Response($request->getMethod() . ' ' . UrlHelper::buildQuery($request->query->all()));
@@ -139,3 +138,14 @@ public function testHandleWithGetRequest() {
   }
 
 }
+
+class TestCustomPageExceptionHtmlSubscriber extends CustomPageExceptionHtmlSubscriber {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function drupalGetDestination() {
+    return ['destination' => 'test'];
+  }
+
+}