CKEditor configuration can't be edited on a Drupal multisite installation

I can't edit CKEditor configuration on my Drupal multisite installation. In the console appears this file not found error

https://........./sites/default/files/civicrm/persist/crm-ckeditor-config.js

It make sense because the file is located on

https://......../sites/SITENAME/files/civicrm/persist/crm-ckeditor-config.js

I was debugging a bit and the problem seems to come from this line https://github.com/civicrm/civicrm-core/blob/master/CRM/Utils/System/Base.php#L580.

$siteName doesn't is on $civicrm_root and for this reason $siteName ever be empty.

Maybe this error will be affecting more components of CiviCRM because the functions getDefaultFileStorage() and getCiviSourceStorage() are involved.