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Django 3.0.1 release notes

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*December 18, 2019*

Django 3.0.1 fixes a security issue and several bugs in 3.0.

CVE-2019-19844: Potential account hijack via password reset form

================================================================

By submitting a suitably crafted email address making use of Unicode

characters, that compared equal to an existing user email when lower-cased for

comparison, an attacker could be sent a password reset token for the matched

account.

In order to avoid this vulnerability, password reset requests now compare the

submitted email using the stricter, recommended algorithm for case-insensitive

comparison of two identifiers from `Unicode Technical Report 36, section

2.11.2(B)(2)`__. Upon a match, the email containing the reset token will be

sent to the email address on record rather than the submitted address.

.. __: https://www.unicode.org/reports/tr36/#Recommendations_General

Bugfixes

========

* Fixed a regression in Django 3.0 by restoring the ability to use Django

  inside Jupyter and other environments that force an async context, by adding

  an option to disable :ref:`async-safety` mechanism with

  :envvar:`DJANGO_ALLOW_ASYNC_UNSAFE` environment variable (:ticket:`31056`).

* Fixed a regression in Django 3.0 where ``RegexPattern``, used by

  :func:`~django.urls.re_path`, returned positional arguments to be passed to

  the view when all optional named groups were missing (:ticket:`31061`).

* Reallowed, following a regression in Django 3.0,

  :class:`~django.db.models.expressions.Window` expressions to be used in

  conditions outside of queryset filters, e.g. in

  :class:`~django.db.models.expressions.When` conditions (:ticket:`31060`).

* Fixed a data loss possibility in

  :class:`~django.contrib.postgres.forms.SplitArrayField`. When using with

  ``ArrayField(BooleanField())``, all values after the first ``True`` value

  were marked as checked instead of preserving passed values (:ticket:`31073`).