XWiki makes title of inaccessible pages available through the class property values REST API
The title of every single page whose reference is known can be accessed through the REST API as long as an XClass with a page property is accessible, this is the default for an XWiki installation. This allows an attacker to get titles of pages whose reference is known, one title per request. This doesn't affect fully private wikis as the REST endpoint checks access rights on the XClass definition. …