Drupal8: Can't upload images via CKEditor/kcfinder
To authenticate, CKEditor calls CRM_Utils_System::loadBootStrap() followed by CRM_Core_Permission::check().
No Drupal8-specific method exists, but when I created one,
CRM_Core_Permission_Drupal8::check() couldn't load the current user. I assume something is failing in the
loadBootstrap() call but I can't figure out what it is.
This SE post seems to contain details, but I'm not Drupal-savvy enough to interpret it.