GHSA-23m2-mghx-vqmf Wagtail: Reflected XSS in dynamic image URL generator view

• PyPI wagtail: >= 7.3, < 7.3.3 → fixed in 7.3.3 • PyPI wagtail: >= 7.4, < 7.4.2 → fixed in 7.4.2

Impact A reflected cross-site scripting (XSS) vulnerability exists on the dynamic image URL generator view within the Wagtail admin interface. A user with a limited-permission editor account for the Wagtail admin could craft a URL that, when viewed by a user with higher privileges, could perform actions with that user's credentials. The vulnerability is present for all sites, even if they do not enable the dynamic image serve view. The vulnerability is not exploitable by an ordinary site visitor without access to the Wagtail admin. Patches Patched versions have been released as Wagtail 7.3.3 and 7.4.2. Workarounds For sites that cannot easily upgrade to a current supported version, the vulnerability can be patched by adding the following code to `urls.py` URL pattern declarations to override the vulnerable view. This disables the admin dynamic image preview functionality, while the public-facing dynamic image serve view still works. ```python from django.http import HttpResponseBadRequest from django.urls import path from wagtail.admin import urls as wagtailadmin_urls def disabled_output(request, image_id): return HttpResponseBadRequest("", content_type="text/plain") urlpatterns = [ # Example where the CMS admin is at /admin/. # Add this before the Wagtail admin URLs registration, with the same sub-path. path("admin/images//generate_url/output/", disabled_output), path("admin/", include(wagtailadmin_urls)), ] ``` Acknowledgements Many thanks to Thibaud Colas (@thibaudcolas) 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).