Wagtail has permission check bypass when editing a model with per-field restrictions through `wagtail.contrib.settings` or `ModelViewSet`

Overview

Impact

If a model has been made available for editing through the wagtail.contrib.settings module or ModelViewSet, and the permission argument on FieldPanel 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.

Patches

Patched versions have been released as Wagtail 6.0.3 and 6.1. Wagtail releases prior to 6.0 are unaffected.

Workarounds

Site owners who are unable to upgrade to a patched version can avoid the vulnerability in ModelViewSet by registering the model as a snippet instead. No workaround is available for wagtail.contrib.settings.

Acknowledgements

Many thanks to Ben Morse and Joshua Munn for reporting this issue.

For more information

If you have any questions or comments about this advisory:

• Visit Wagtail's support channels
• Email us at [email protected] (view our security policy for more information).

Affected packages

• wagtail >= 6.0.0, < 6.0.3

Remediation

Upgrade to a patched release:

• wagtail 6.0.3