diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index 06acf935e013b1f0977412170eb43b5f3b61c84f..d5963a0aff7e117618c4836862cc53100ac47cbe 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -2778,6 +2778,11 @@ function _drupal_bootstrap_variables() {
       unset($_GET['destination']);
       unset($_REQUEST['destination']);
     }
+    // Use the DrupalRequestSanitizer to ensure that the destination's query
+    // parameters are not dangerous.
+    if (isset($_GET['destination'])) {
+      DrupalRequestSanitizer::cleanDestination();
+    }
     // If there's still something in $_REQUEST['destination'] that didn't come
     // from $_GET, check it too.
     if (isset($_REQUEST['destination']) && (!isset($_GET['destination']) || $_REQUEST['destination'] != $_GET['destination']) && url_is_external($_REQUEST['destination'])) {
diff --git a/includes/common.inc b/includes/common.inc
index d7dc47f229ea75d375fd35ddab2a17aad26cd4ca..f61d1eb0f2496a4afd186715765773eb20ddfc33 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -611,8 +611,9 @@ function drupal_parse_url($url) {
   }
   // The 'q' parameter contains the path of the current page if clean URLs are
   // disabled. It overrides the 'path' of the URL when present, even if clean
-  // URLs are enabled, due to how Apache rewriting rules work.
-  if (isset($options['query']['q'])) {
+  // URLs are enabled, due to how Apache rewriting rules work. The path
+  // parameter must be a string.
+  if (isset($options['query']['q']) && is_string($options['query']['q'])) {
     $options['path'] = $options['query']['q'];
     unset($options['query']['q']);
   }
diff --git a/includes/request-sanitizer.inc b/includes/request-sanitizer.inc
index 1daa6b53485d76715541e5d4ce6ddffa90293a43..7214436b8ad18e04626cd6a401d2d37d1279769d 100644
--- a/includes/request-sanitizer.inc
+++ b/includes/request-sanitizer.inc
@@ -51,6 +51,38 @@ public static function sanitize() {
     }
   }
 
+  /**
+   * Removes the destination if it is dangerous.
+   *
+   * Note this can only be called after common.inc has been included.
+   *
+   * @return bool
+   *   TRUE if the destination has been removed from $_GET, FALSE if not.
+   */
+  public static function cleanDestination() {
+    $dangerous_keys = array();
+    $log_sanitized_keys = variable_get('sanitize_input_logging', FALSE);
+
+    $parts = drupal_parse_url($_GET['destination']);
+    // If there is a query string, check its query parameters.
+    if (!empty($parts['query'])) {
+      $whitelist = variable_get('sanitize_input_whitelist', array());
+
+      self::stripDangerousValues($parts['query'], $whitelist, $dangerous_keys);
+      if (!empty($dangerous_keys)) {
+        // The destination is removed rather than sanitized to mirror the
+        // handling of external destinations.
+        unset($_GET['destination']);
+        unset($_REQUEST['destination']);
+        if ($log_sanitized_keys) {
+          trigger_error(format_string('Potentially unsafe destination removed from query string parameters (GET) because it contained the following keys: @keys', array('@keys' => implode(', ', $dangerous_keys))));
+        }
+        return TRUE;
+      }
+    }
+    return FALSE;
+  }
+
   /**
    * Strips dangerous keys from the provided input.
    *
diff --git a/modules/file/file.module b/modules/file/file.module
index 1e98f11bd7caa49fa79be7962347ce497c66962a..eea58470fab2deb007c9ba99b3bf3afbcaf4acb2 100644
--- a/modules/file/file.module
+++ b/modules/file/file.module
@@ -239,6 +239,9 @@ function file_ajax_upload() {
   $form_parents = func_get_args();
   $form_build_id = (string) array_pop($form_parents);
 
+  // Sanitize form parents before using them.
+  $form_parents = array_filter($form_parents, 'element_child');
+
   if (empty($_POST['form_build_id']) || $form_build_id != $_POST['form_build_id']) {
     // Invalid request.
     drupal_set_message(t('An unrecoverable error occurred. The uploaded file likely exceeded the maximum file size (@size) that this server supports.', array('@size' => format_size(file_upload_max_size()))), 'error');