Wagtail is an open source content management system built on Django. Prior to versions 6.3.6, 7.0.4, 7.1.3, 7.2.2, and 7.3, due to a missing permission check on the preview endpoints, a user with access to the Wagtail admin and knowledge of a model's fields can craft a form submission to obtain a preview rendering of any page, snippet or site setting object for which previews are enabled, consisting of any data of the user's choosing. The existing data of the object itself is not exposed, but depending on the nature of the template being rendered, this may expose other database contents that would otherwise only be accessible to users with edit access over the model. The vulnerability is not exploitable by an ordinary site visitor without access to the Wagtail admin. This issue has been patched in versions 6.3.6, 7.0.4, 7.1.3, 7.2.2, and 7.3.

Wagtail has improper permission handling on admin preview endpoints