GHSA-r6p4-grq7-xm4m: Medium severity pip/wagtail vulnerability

Impact Due to a missing permission check on the image preview endpoint, a user with access to the Wagtail admin can preview any image. The existing data of the image object itself is not exposed. The vulnerability is not exploitable by an ordinary site visitor without access to the Wagtail admin.

Patches Patched versions have been released as Wagtail 7.0.8, 7.3.3, 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.

python from django.core.exceptions import PermissionDenied from django.shortcuts import getobjector404 from django.urls import path from wagtail.admin import urls as wagtailadminurls from wagtail.images.permissions import permissionpolicy from wagtail.images.views import preview

def patchedpreview(request, imageid, filterspec): image = getobjector404(getimagemodel(), id=imageid)

if not permissionpolicy.userhaspermissionforinstance(request.user, "change", image): raise PermissionDenied

return preview(request, imageid, filterspec)

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/<int:imageid>/preview/<str:filterspec>/", patchedpreview) path("admin/", include(wagtailadminurls)), ]

Acknowledgements Many thanks to @0x1saac and @harshakshit for reporting this issue.

For more information If you have any questions or comments about this advisory:

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