diff --git a/core/includes/common.inc b/core/includes/common.inc
index b9f2d8f..ec88c45 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -19,6 +19,7 @@
 use Drupal\Component\Utility\String;
 use Drupal\Component\Utility\Tags;
 use Drupal\Component\Utility\UrlHelper;
+use Drupal\Component\Utility\Xss;
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Site\Settings;
@@ -3126,6 +3127,23 @@ function drupal_render(&$elements, $is_recursive_call = FALSE) {
     $elements['#markup'] = SafeMarkup::set($elements['#markup']);
   }
 
+  // Filtering keys which are expected to contain HTML.
+  $markup_keys = array(
+    '#description',
+    '#field_prefix',
+    '#field_suffix',
+    '#prefix',
+    '#suffix',
+  );
+  foreach ($markup_keys as $key) {
+    if (!empty($elements[$key]) && !is_array($elements[$key])) {
+      $elements[$key] = Xss::filterAdmin($elements[$key]);
+    }
+    else {
+      $elements[$key] = NULL;
+    }
+  }
+
   // Assume that if #theme is set it represents an implemented hook.
   $theme_is_implemented = isset($elements['#theme']);
 
@@ -3214,6 +3232,7 @@ function drupal_render(&$elements, $is_recursive_call = FALSE) {
   // #cache is disabled, #cache is enabled, there is a cache hit or miss.
   $prefix = isset($elements['#prefix']) ? $elements['#prefix'] : '';
   $suffix = isset($elements['#suffix']) ? $elements['#suffix'] : '';
+
   $elements['#markup'] = $prefix . $elements['#children'] . $suffix;
 
   // Collect all #post_render_cache callbacks associated with this element when:
diff --git a/core/modules/field_ui/src/Tests/FieldUiTestBase.php b/core/modules/field_ui/src/Tests/FieldUiTestBase.php
index 6157893..421500c 100644
--- a/core/modules/field_ui/src/Tests/FieldUiTestBase.php
+++ b/core/modules/field_ui/src/Tests/FieldUiTestBase.php
@@ -78,6 +78,7 @@ function fieldUIAddNewField($bundle_path, $initial_edit, $field_edit = array(),
 
     // Second step : 'Field settings' form.
     $this->drupalPostForm(NULL, $field_edit, t('Save field settings'));
+    $this->assertNoRaw('<', 'The page does not have double escaped HTML tags.');
     $this->assertRaw(t('Updated field %label field settings.', array('%label' => $label)), 'Redirected to instance and widget settings page.');
 
     // Third step : 'Instance settings' form.
@@ -105,6 +106,7 @@ function fieldUIAddExistingField($bundle_path, $initial_edit, $instance_edit = a
 
     // First step : 'Re-use existing field' on the 'Manage fields' page.
     $this->drupalPostForm("$bundle_path/fields", $initial_edit, t('Save'));
+    $this->assertNoRaw('<', 'The page does not have double escaped HTML tags.');
 
     // Second step : 'Instance settings' form.
     $this->drupalPostForm(NULL, $instance_edit, t('Save settings'));
diff --git a/core/modules/field_ui/src/Tests/ManageFieldsTest.php b/core/modules/field_ui/src/Tests/ManageFieldsTest.php
index c137308..201f5f6 100644
--- a/core/modules/field_ui/src/Tests/ManageFieldsTest.php
+++ b/core/modules/field_ui/src/Tests/ManageFieldsTest.php
@@ -141,6 +141,7 @@ function updateField() {
 
     // Go to the field instance edit page.
     $this->drupalGet('admin/structure/types/manage/' . $this->type . '/fields/' . $instance_id);
+    $this->assertNoRaw('<', 'The page does not have double escaped HTML tags.');
     $edit = array(
       'instance[settings][test_instance_setting]' => $string,
     );
@@ -221,6 +222,7 @@ protected function deleteFieldInstance() {
     // Delete the field instance.
     $instance_id = 'node.' . $this->type . '.' . $this->field_name;
     $this->drupalGet('admin/structure/types/manage/' . $this->type . '/fields/' . $instance_id);
+    $this->assertNoRaw('<', 'The page does not have double escaped HTML tags.');
     $this->drupalPostForm(NULL, array(), t('Delete field'));
     $this->assertResponse(200);
   }
@@ -564,6 +566,9 @@ function testHelpDescriptions() {
 
     entity_get_form_display('node', 'article', 'default')->setComponent('field_image')->save();
 
+    $this->drupalGet('admin/structure/types/manage/article/fields/node.article.field_image');
+    $this->assertNoRaw('<div', 'Image fields do not have double escaped HTML tags.');
+
     $edit = array(
       'instance[description]' => '<strong>Test with an upload field.',
     );
diff --git a/core/modules/locale/src/Form/ImportForm.php b/core/modules/locale/src/Form/ImportForm.php
index 426187f..75dda76 100644
--- a/core/modules/locale/src/Form/ImportForm.php
+++ b/core/modules/locale/src/Form/ImportForm.php
@@ -103,18 +103,22 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       'file_validate_extensions' => array('po'),
       'file_validate_size' => array(file_upload_max_size()),
     );
+
+    $file_description = array(
+      '#theme' => 'file_upload_help',
+      '#description' => $this->t('A Gettext Portable Object file.'),
+      '#upload_validators' => $validators,
+    );
+
     $form['file'] = array(
       '#type' => 'file',
       '#title' => $this->t('Translation file'),
-      '#description' => array(
-        '#theme' => 'file_upload_help',
-        '#description' => $this->t('A Gettext Portable Object file.'),
-        '#upload_validators' => $validators,
-      ),
+      '#description' => drupal_render($file_description),
       '#size' => 50,
       '#upload_validators' => $validators,
       '#attributes' => array('class' => array('file-import-input')),
     );
+
     $form['langcode'] = array(
       '#type' => 'select',
       '#title' => $this->t('Language'),
diff --git a/core/modules/options/src/Tests/OptionsFieldUITest.php b/core/modules/options/src/Tests/OptionsFieldUITest.php
index ebbba4b..70bf9d4 100644
--- a/core/modules/options/src/Tests/OptionsFieldUITest.php
+++ b/core/modules/options/src/Tests/OptionsFieldUITest.php
@@ -278,6 +278,7 @@ protected function createOptionsField($type) {
   function assertAllowedValuesInput($input_string, $result, $message) {
     $edit = array('field[settings][allowed_values]' => $input_string);
     $this->drupalPostForm($this->admin_path, $edit, t('Save field settings'));
+    $this->assertNoRaw('&amp;lt;', 'The page does not have double escaped HTML tags.');
 
     if (is_string($result)) {
       $this->assertText($result, $message);