django/django

===========================
Django 1.4.20 release notes
===========================

*March 18, 2015*

Django 1.4.20 fixes one security issue in 1.4.19.

Mitigated possible XSS attack via user-supplied redirect URLs
=============================================================

Django relies on user input in some cases (e.g.
``django.contrib.auth.views.login()`` and :doc:`i18n </topics/i18n/index>`)
to redirect the user to an "on success" URL. The security checks for these
redirects (namely ``django.utils.http.is_safe_url()``) accepted URLs with
leading control characters and so considered URLs like ``\x08javascript:...``
safe. This issue doesn't affect Django currently, since we only put this URL
into the ``Location`` response header and browsers seem to ignore JavaScript
there. Browsers we tested also treat URLs prefixed with control characters such
as ``%08//example.com`` as relative paths so redirection to an unsafe target
isn't a problem either.

However, if a developer relies on ``is_safe_url()`` to
provide safe redirect targets and puts such a URL into a link, they could
suffer from an XSS attack as some browsers such as Google Chrome ignore control
characters at the start of a URL in an anchor ``href``.