Vulnerability Instance

Wagtail has permission check bypass when editing a model with per-field restrictions through `wagtail.contrib.settings` or `ModelViewSet`
If a model has been made available for editing through the [`wagtail.contrib.settings`](https://docs.wagtail.org/en/stable/reference/contrib/settings.html) module or [`ModelViewSet`](https://docs.wagtail.org/en/stable/extending/generic_views.html#modelviewset), and the [`permission` argument on `FieldPanel`](https://docs.wagtail.org/en/stable/reference/pages/panels.html#wagtail.admin.panels.FieldPanel.permission) has been used to further restrict access to one or more fields of the model, a user with edit permission over the model but not the specific field can craft an HTTP POST request that bypasses the permission check on the individual field, allowing them to update its value.

The vulnerability is not exploitable by an ordinary site visitor without access to the Wagtail admin, or by a user who has not been granted edit access to the model in question. The editing interfaces for pages and snippets are also unaffected.