diff --git a/core/modules/media/src/Plugin/media/Source/OEmbed.php b/core/modules/media/src/Plugin/media/Source/OEmbed.php
index 6a3621a3b5a95381db6a62bf4ebbc288f0948cef..58a819c25a7bd0f1acfbc8946f3ea1fc8aec7962 100644
--- a/core/modules/media/src/Plugin/media/Source/OEmbed.php
+++ b/core/modules/media/src/Plugin/media/Source/OEmbed.php
@@ -394,10 +394,14 @@ protected function getLocalThumbnailUri(Resource $resource) {
     }
     $remote_thumbnail_url = $remote_thumbnail_url->toString();
 
+    // Remove the query string, since we do not want to include it in the local
+    // thumbnail URI.
+    $local_thumbnail_url = parse_url($remote_thumbnail_url, PHP_URL_PATH);
+
     // Compute the local thumbnail URI, regardless of whether or not it exists.
     $configuration = $this->getConfiguration();
     $directory = $configuration['thumbnails_directory'];
-    $local_thumbnail_uri = "$directory/" . Crypt::hashBase64($remote_thumbnail_url) . '.' . pathinfo($remote_thumbnail_url, PATHINFO_EXTENSION);
+    $local_thumbnail_uri = "$directory/" . Crypt::hashBase64($local_thumbnail_url) . '.' . pathinfo($local_thumbnail_url, PATHINFO_EXTENSION);
 
     // If the local thumbnail already exists, return its URI.
     if (file_exists($local_thumbnail_uri)) {
diff --git a/core/modules/media/tests/src/Kernel/OEmbedSourceTest.php b/core/modules/media/tests/src/Kernel/OEmbedSourceTest.php
index 180085ae04c53140bbb4abb7a5247bfc7a765bb5..d2c2414e1243a520dcb30986ce77c8dc638edb2d 100644
--- a/core/modules/media/tests/src/Kernel/OEmbedSourceTest.php
+++ b/core/modules/media/tests/src/Kernel/OEmbedSourceTest.php
@@ -2,20 +2,23 @@
 
 namespace Drupal\Tests\media\Kernel;
 
-use Drupal\KernelTests\KernelTestBase;
+use Drupal\Component\Utility\Crypt;
+use Drupal\Core\Url;
+use Drupal\media\Entity\Media;
+use Drupal\media\OEmbed\Resource;
+use Drupal\media\OEmbed\ResourceFetcherInterface;
+use Drupal\media\OEmbed\UrlResolverInterface;
 use Drupal\media\Plugin\media\Source\OEmbed;
+use GuzzleHttp\Client;
+use GuzzleHttp\Psr7\Response;
+use Prophecy\Argument;
 
 /**
  * @coversDefaultClass \Drupal\media\Plugin\media\Source\OEmbed
  *
  * @group media
  */
-class OEmbedSourceTest extends KernelTestBase {
-
-  /**
-   * {@inheritdoc}
-   */
-  protected static $modules = ['media'];
+class OEmbedSourceTest extends MediaKernelTestBase {
 
   /**
    * @covers ::getMetadata
@@ -34,4 +37,49 @@ public function testGetMetadata() {
     $this->assertNull($plugin->getMetadata($media->reveal(), 'type'));
   }
 
+  /**
+   * @covers ::getLocalThumbnailUri
+   */
+  public function testLocalThumbnailUriQueryStringIsIgnored() {
+    // There's no need to resolve the resource URL in this test; we just need
+    // to fetch the resource.
+    $this->container->set(
+      'media.oembed.url_resolver',
+      $this->prophesize(UrlResolverInterface::class)->reveal()
+    );
+
+    $thumbnail_url = Url::fromUri('internal:/core/misc/druplicon.png?foo=bar');
+
+    // Create a mocked resource whose thumbnail URL contains a query string.
+    $resource = $this->prophesize(Resource::class);
+    $resource->getTitle()->willReturn('Test resource');
+    $resource->getThumbnailUrl()->willReturn($thumbnail_url);
+
+    // The source plugin will try to fetch the remote thumbnail, so mock the
+    // HTTP client to ensure that request returns an empty "OK" response.
+    $http_client = $this->prophesize(Client::class);
+    $http_client->get(Argument::type('string'))->willReturn(new Response());
+    $this->container->set('http_client', $http_client->reveal());
+
+    // Mock the resource fetcher so that it will return our mocked resource.
+    $resource_fetcher = $this->prophesize(ResourceFetcherInterface::class);
+    $resource_fetcher->fetchResource(NULL)->willReturn($resource->reveal());
+    $this->container->set('media.oembed.resource_fetcher', $resource_fetcher->reveal());
+
+    $media_type = $this->createMediaType('oembed:video');
+    $source = $media_type->getSource();
+
+    $media = Media::create([
+      'bundle' => $media_type->id(),
+      $source->getSourceFieldDefinition($media_type)->getName() => $this->randomString(),
+    ]);
+    $media->save();
+
+    // Get the local thumbnail URI and ensure that it does not contain any
+    // query string.
+    $local_thumbnail_uri = $media_type->getSource()->getMetadata($media, 'thumbnail_uri');
+    $expected_uri = 'public://oembed_thumbnails/' . Crypt::hashBase64('/core/misc/druplicon.png') . '.png';
+    $this->assertSame($expected_uri, $local_thumbnail_uri);
+  }
+
 }