diff --git a/core/modules/serialization/src/EventSubscriber/DefaultExceptionSubscriber.php b/core/modules/serialization/src/EventSubscriber/DefaultExceptionSubscriber.php
index bc1210a..5774a31 100644
--- a/core/modules/serialization/src/EventSubscriber/DefaultExceptionSubscriber.php
+++ b/core/modules/serialization/src/EventSubscriber/DefaultExceptionSubscriber.php
@@ -3,10 +3,8 @@
 namespace Drupal\serialization\EventSubscriber;
 
 use Drupal\Core\EventSubscriber\HttpExceptionSubscriberBase;
-use Drupal\Core\EventSubscriber\MainContentViewSubscriber;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
-use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
 use Symfony\Component\Serializer\SerializerInterface;
 
 /**
@@ -58,26 +56,69 @@ protected static function getPriority() {
   }
 
   /**
-   * {@inheritdoc}
+   * Handles a 400 error for HTTP.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
+   *   The event to process.
    */
-  public function onException(GetResponseForExceptionEvent $event) {
-    $exception = $event->getException();
+  public function on400(GetResponseForExceptionEvent $event) {
+    $this->setEventResponse($event, Response::HTTP_BAD_REQUEST);
+  }
 
-    // Make the exception available for example when rendering a block.
-    $request = $event->getRequest();
-    $request->attributes->set('exception', $exception);
+  /**
+   * Handles a 403 error for HTTP.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
+   *   The event to process.
+   */
+  public function on403(GetResponseForExceptionEvent $event) {
+    $this->setEventResponse($event, Response::HTTP_FORBIDDEN);
+  }
 
-    $handled_formats = $this->getHandledFormats();
+  /**
+   * Handles a 404 error for HTTP.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
+   *   The event to process.
+   */
+  public function on404(GetResponseForExceptionEvent $event) {
+    $this->setEventResponse($event, Response::HTTP_NOT_FOUND);
+  }
 
-    $format = $request->query->get(MainContentViewSubscriber::WRAPPER_FORMAT, $request->getRequestFormat());
+  /**
+   * Handles a 405 error for HTTP.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
+   *   The event to process.
+   */
+  public function on405(GetResponseForExceptionEvent $event) {
+    $this->setEventResponse($event, Response::HTTP_METHOD_NOT_ALLOWED);
+  }
 
-    if ($exception instanceof HttpExceptionInterface && in_array($format, $handled_formats)) {
-      $format = $event->getRequest()->getRequestFormat();
-      $content = ['message' => $event->getException()->getMessage()];
-      $encoded_content = $this->serializer->serialize($content, $format);
-      $response = new Response($encoded_content, $exception->getStatusCode());
-      $event->setResponse($response);
-    }
+  /**
+   * Handles a 406 error for HTTP.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
+   *   The event to process.
+   */
+  public function on406(GetResponseForExceptionEvent $event) {
+    $this->setEventResponse($event, Response::HTTP_NOT_ACCEPTABLE);
+  }
+
+  /**
+   * Sets the Response for the exception event.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
+   *   The current exception event.
+   * @param int $status
+   *   The HTTP status code to set for the response.
+   */
+  protected function setEventResponse(GetResponseForExceptionEvent $event, $status) {
+    $format = $event->getRequest()->getRequestFormat();
+    $content = ['message' => $event->getException()->getMessage()];
+    $encoded_content = $this->serializer->serialize($content, $format);
+    $response = new Response($encoded_content, $status);
+    $event->setResponse($response);
   }
 
 }
diff --git a/core/modules/user/tests/src/Functional/UserLoginHttpTest.php b/core/modules/user/tests/src/Functional/UserLoginHttpTest.php
index 7484b8c..6d4b020 100644
--- a/core/modules/user/tests/src/Functional/UserLoginHttpTest.php
+++ b/core/modules/user/tests/src/Functional/UserLoginHttpTest.php
@@ -106,7 +106,7 @@ public function testLogin() {
         $user_login_status_url->setRouteParameter('_format', $format);
         $user_login_status_url->setAbsolute();
 
-        $response = $client->post($user_login_status_url->toString());
+        $response = $client->get($user_login_status_url->toString());
         $this->assertResponse($response, 200, UserAuthenticationController::LOGGED_OUT);
 
         // Flooded.
@@ -163,14 +163,14 @@ public function testLogin() {
         $result_data = $this->decode($response->getBody(), $format);
         $this->assertEquals($name, $result_data['current_user']['name']);
 
-        $response = $client->post($user_login_status_url->toString(), ['cookies' => $this->cookies]);
+        $response = $client->get($user_login_status_url->toString(), ['cookies' => $this->cookies]);
         $this->assertEquals(200, $response->getStatusCode());
         $this->assertEquals(UserAuthenticationController::LOGGED_IN, (string) $response->getBody());
 
         $response = $this->logoutRequest($format);
         $this->assertEquals(204, $response->getStatusCode());
 
-        $response = $client->post($user_login_status_url->toString(), ['cookies' => $this->cookies]);
+        $response = $client->get($user_login_status_url->toString(), ['cookies' => $this->cookies]);
         $this->assertResponse($response, 200, UserAuthenticationController::LOGGED_OUT);
 
         $this->resetFlood();
diff --git a/core/modules/user/user.routing.yml b/core/modules/user/user.routing.yml
index 09ac772..9cf1949 100644
--- a/core/modules/user/user.routing.yml
+++ b/core/modules/user/user.routing.yml
@@ -142,7 +142,7 @@ user.login_status.http:
   path: '/user/login_status'
   defaults:
     _controller: \Drupal\user\Controller\UserAuthenticationController::loginStatus
-  methods: [POST]
+  methods: [GET]
   requirements:
     _access: 'TRUE'
     _format: 'json'