diff --git a/core/lib/Drupal/Component/Utility/Url.php b/core/lib/Drupal/Component/Utility/Url.php
index 07d959e..88eb752 100644
--- a/core/lib/Drupal/Component/Utility/Url.php
+++ b/core/lib/Drupal/Component/Utility/Url.php
@@ -228,7 +228,7 @@ public static function externalIsLocal($url, $base_url) {
     $base_host = parse_url($base_url, PHP_URL_HOST);
     $base_url = substr($base_url, strpos($base_url, $base_host) + strlen($base_host));
 
-    if (!isset($url_parts['path'])) {
+    if (!isset($url_parts['path']) || $url_parts['path'] == '/') {
       return ($url_parts['host'] == $base_host);
     }
     else {
diff --git a/core/tests/Drupal/Tests/Component/Utility/UrlTest.php b/core/tests/Drupal/Tests/Component/Utility/UrlTest.php
index b4e0e3e..31d767e 100644
--- a/core/tests/Drupal/Tests/Component/Utility/UrlTest.php
+++ b/core/tests/Drupal/Tests/Component/Utility/UrlTest.php
@@ -409,13 +409,28 @@ protected function dataEnhanceWithPrefix(array $urls) {
   }
 
   /**
+   * Data provider for testExternalIsLocal()
+   */
+  public function providerTestExternalIsLocal() {
+    return array (
+      array('http://example.com/url', 'http://example.com/', TRUE),
+      array('http://example.com/url', 'http://moexample.com/', FALSE),
+      array('http://example.com/', 'http://example.com/', TRUE),
+      array('http://example.com', 'http://example.com/', TRUE),
+      array('http://example.com/', 'http://example.com', TRUE),
+      array('http://example.com', 'http://example.com', TRUE),
+    );
+  }
+
+  /**
    * Test externalIsLocal method.
    *
+   * @dataProvider providerTestExternalIsLocal
+   *
    * @see \Drupal\Component\Utility\Url::externalIsLocal()
    */
-  public function testExternalIsLocal() {
-    $this->assertTrue(Url::externalIsLocal('http://example.com/url', 'http://example.com/'));
-    $this->assertFalse(Url::externalIsLocal('http://example.com/url', 'http://moexample.com/'));
+  public function testExternalIsLocal($url, $base_url, $expected) {
+    $this->assertEquals(Url::externalIsLocal($url, $base_url), $expected);
   }
 
 }