# Django 5.2.16 documentation

# Django 4.2.5 release notes

September 4, 2023

Django 4.2.5 fixes a security issue with severity “moderate” and several bugs in 4.2.4.

## CVE-2023-41164: Potential denial of service vulnerability in `django.utils.encoding.uri_to_iri()`

`django.utils.encoding.uri_to_iri()` was subject to potential denial of service attack via certain inputs with a very large number of Unicode characters.

## Bugfixes

- Fixed a regression in Django 4.2 that caused an incorrect validation of `CheckConstraints` on `__isnull` lookups against `JSONField` (#34754).

- Fixed a bug in Django 4.2 where the deprecated `DEFAULT_FILE_STORAGE` and `STATICFILES_STORAGE` settings were not synced with `STORAGES` (#34773).

- Fixed a regression in Django 4.2.2 that caused an unnecessary selection of a non-nullable `ManyToManyField` without a natural key during serialization (#34779).

- Fixed a regression in Django 4.2 that caused a crash of a queryset when filtering against deeply nested `OuterRef()` annotations (#34803).