diff --git a/core/lib/Drupal/Core/Routing/ContentTypeHeaderMatcher.php b/core/lib/Drupal/Core/Routing/ContentTypeHeaderMatcher.php
index 7d66b50ecefd80ce5b5584fc07217030d85e54b8..d6452e8be03e6b9c1576c4a585d4cb2db4d2bce7 100644
--- a/core/lib/Drupal/Core/Routing/ContentTypeHeaderMatcher.php
+++ b/core/lib/Drupal/Core/Routing/ContentTypeHeaderMatcher.php
@@ -42,7 +42,7 @@ public function filter(RouteCollection $collection, Request $request) {
     // We do not throw a
     // \Symfony\Component\Routing\Exception\ResourceNotFoundException here
     // because we don't want to return a 404 status code, but rather a 415.
-    if (!$request->headers->has('Content-Type')) {
+    if (!$request->headers->get('Content-Type', FALSE)) {
       throw new UnsupportedMediaTypeHttpException('No "Content-Type" request header specified');
     }
     else {