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Date: Thu, 6 May 2021 09:50:26 +0200
From: Mariusz Felisiak <>
Subject: Django: CVE-2021-32052: Header injection possibility since
 URLValidator accepted newlines in input on Python 3.9.5+

In accordance with `our security release policy
<>`_, the 
Django team
is issuing
`Django 3.2.2 <>`_,
`Django 3.1.10 
<>`_, and
`Django 2.2.22 <>`_.
These releases address the security issue with severity "moderate" 
detailed below. We encourage all users of Django to upgrade as soon as 

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

On Python 3.9.5+, ``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 
``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.

Affected supported versions

* Django main branch
* Django 3.2
* Django 3.1
* Django 2.2


Patches to resolve the issue have been applied to Django's main branch 
and to
the 3.2, 3.1, and 2.2 release branches. The patches may be obtained from the
following changesets:

* On the `main branch 
* On the `3.2 release branch 
* On the `3.1 release branch 
* On the `2.2 release branch 

The following releases have been issued:

* Django 3.2.2 (`download Django 3.2.2 
<>`_ | 
`3.2.2 checksums 
* Django 3.1.10 (`download Django 3.1.10 
<>`_ | 
`3.1.10 checksums 
* Django 2.2.22 (`download Django 2.2.22 
<>`_ | 
`2.2.22 checksums 

The PGP key ID used for this release is Mariusz Felisiak: 
`2EF56372BA48CD1B <>`_.

General notes regarding security reporting

As always, we ask that potential security issues be reported via
private email to ````, and not via Django's
Trac instance or the django-developers list. Please see `our security
policies <>`_ for further

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