Django

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

*January 4, 2022*

Django 2.2.26 fixes one security issue with severity "medium" and two security
issues with severity "low" in 2.2.25.

CVE-2021-45115: Denial-of-service possibility in ``UserAttributeSimilarityValidator``
=====================================================================================

:class:`.UserAttributeSimilarityValidator` incurred significant overhead
evaluating submitted password that were artificially large in relative to the
comparison values. On the assumption that access to user registration was
unrestricted this provided a potential vector for a denial-of-service attack.

In order to mitigate this issue, relatively long values are now ignored by
``UserAttributeSimilarityValidator``.

This issue has severity "medium" according to the :ref:`Django security policy
<security-disclosure>`.

CVE-2021-45116: Potential information disclosure in ``dictsort`` template filter
================================================================================

Due to leveraging the Django Template Language's variable resolution logic, the
:tfilter:`dictsort` template filter was potentially vulnerable to information
disclosure or unintended method calls, if passed a suitably crafted key.

In order to avoid this possibility, ``dictsort`` now works with a restricted
resolution logic, that will not call methods, nor allow indexing on
dictionaries.

As a reminder, all untrusted user input should be validated before use.

This issue has severity "low" according to the :ref:`Django security policy
<security-disclosure>`.

CVE-2021-45452: Potential directory-traversal via ``Storage.save()``
====================================================================

``Storage.save()`` allowed directory-traversal if directly passed suitably
crafted file names.

This issue has severity "low" according to the :ref:`Django security policy
<security-disclosure>`.


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

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

*December 7, 2021*

Django 2.2.25 fixes a security issue with severity "low" in 2.2.24.

CVE-2021-44420: Potential bypass of an upstream access control based on URL paths
=================================================================================

HTTP requests for URLs with trailing newlines could bypass an upstream access
control based on URL paths.


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

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

*June 2, 2021*

Django 2.2.24 fixes two security issues in 2.2.23.

CVE-2021-33203: Potential directory traversal via ``admindocs``
===============================================================

Staff members could use the :mod:`~django.contrib.admindocs`
``TemplateDetailView`` view to check the existence of arbitrary files.
Additionally, if (and only if) the default admindocs templates have been
customized by the developers to also expose the file contents, then not only
the existence but also the file contents would have been exposed.

As a mitigation, path sanitation is now applied and only files within the
template root directories can be loaded.

CVE-2021-33571: Possible indeterminate SSRF, RFI, and LFI attacks since validators accepted leading zeros in IPv4 addresses
===========================================================================================================================

:class:`~django.core.validators.URLValidator`,
:func:`~django.core.validators.validate_ipv4_address`, and
:func:`~django.core.validators.validate_ipv46_address` didn't prohibit leading
zeros in octal literals. If you used such values you could suffer from
indeterminate SSRF, RFI, and LFI attacks.

:func:`~django.core.validators.validate_ipv4_address` and
:func:`~django.core.validators.validate_ipv46_address` validators were not
affected on Python 3.9.5+.


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

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

*May 13, 2021*

Django 2.2.23 fixes a regression in 2.2.21.

Bugfixes
========

* Fixed a regression in Django 2.2.21 where saving ``FileField`` would raise a
``SuspiciousFileOperation`` even when a custom
:attr:`~django.db.models.FileField.upload_to` returns a valid file path
(:ticket:`32718`).


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

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

*May 6, 2021*

Django 2.2.22 fixes a security issue in 2.2.21.

CVE-2021-32052: Header injection possibility since ``URLValidator`` accepted newlines in input on Python 3.9.5+
===============================================================================================================

On Python 3.9.5+, :class:`~django.core.validators.URLValidator` didn't prohibit
newlines and tabs. If you used values with newlines in HTTP response, you could
suffer from header injection attacks. Django itself wasn't vulnerable because
:class:`~django.http.HttpResponse` prohibits newlines in HTTP headers.

Moreover, the ``URLField`` form field which uses ``URLValidator`` silently
removes newlines and tabs on Python 3.9.5+, so the possibility of newlines
entering your data only existed if you are using this validator outside of the
form fields.

This issue was introduced by the :bpo:`43882` fix.


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

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

*May 4, 2021*

Django 2.2.21 fixes a security issue in 2.2.20.

CVE-2021-31542: Potential directory-traversal via uploaded files
================================================================

``MultiPartParser``, ``UploadedFile``, and ``FieldFile`` allowed
directory-traversal via uploaded files with suitably crafted file names.

In order to mitigate this risk, stricter basename and path sanitation is now
applied.


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