A flaw was found in Django. Model formsets did not correctly validate primary key values submitted in forged POST data when a model's primary key could be set through the form itself, such as with a OneToOneField (or a parent link used as the primary key of an inline formset's model), or a natural or UUID primary key included among the form's fields. An attacker with access to submit data to such a formset could forge POST data referencing primary keys outside the formset's limiting queryset, causing the formset to delete instances outside that queryset, or create instances through what was intended to be an edit-only formset. Models using the default BigAutoField primary key are not affected, since the primary key is not attacker-settable through the form.