images added with WYSIWYG in category description are uploaded into admin-directory

[emil-777]

Preconditions

1. PHP 7
2. Magento 2.1.2

Steps to reproduce

When I'm uploading an image with the WYSIWYG-editor for the category description, the image is uploaded - and its' path which is used in the src-attribute of img-tag to the admin directory (domain.com/admin_veuCvtf/...).
I assume it has to be located in pub/media./.. directory. Otherwise the name of the backend login is disclosed.

Expected result

The uploaded image is located in /pub/media/... directory.

Actual result

In the img-src-tag the file is located in domain.com/admin_veuCvtf/.. directory.

[devhn]

Similar to #6138?

[emil-777]

yes, seems to be similar

[magento-team]

Internal ticket to track issue progress: MAGETWO-70435