django/django

==========================
Django 4.1.6 release notes
==========================

*February 1, 2023*

Django 4.1.6 fixes a security issue with severity "moderate" and a bug in
4.1.5.

CVE-2023-23969: Potential denial-of-service via ``Accept-Language`` headers
===========================================================================

The parsed values of ``Accept-Language`` headers are cached in order to avoid
repetitive parsing. This leads to a potential denial-of-service vector via
excessive memory usage if large header values are sent.

In order to avoid this vulnerability, the ``Accept-Language`` header is now
parsed up to a maximum length.

Bugfixes
========

* Fixed a bug in Django 4.1 that caused a crash of model validation on
  ``UniqueConstraint`` with ordered expressions (:ticket:`34291`).