Security releases issued

Posted by James Bennett on October 17, 2012

Today the Django team is issuing multiple releases -- Django 1.3.4 and Django 1.4.2 -- to remedy security issues reported to us.

All users are encouraged to upgrade Django immediately.

Host header poisoning

Some parts of Django -- independent of end-user-written applications -- make use of full URLs, including domain name, which are generated from the HTTP Host header. Some attacks against this are beyond Django's ability to control, and require the web server to be properly configured; Django's documentation has for some time contained notes advising users on such configuration.

Django's own built-in parsing of the Host header is, however, still vulnerable, as was reported to us recently. The Host header parsing in Django 1.3 and Django 1.4 -- specifically, django.http.HttpRequest.get_host() -- was incorrectly handling username/password information in the header. Thus, for example, the following Host header would be accepted by Django when running on "":


Using this, an attacker can cause parts of Django -- particularly the password-reset mechanism -- to generate and display arbitrary URLs to users.

To remedy this, the parsing in HttpRequest.get_host() is being modified; Host headers which contain potentially dangerous content (such as username/password pairs) now raise the exception django.core.exceptions.SuspiciousOperation.

Documentation of HttpOnly cookie option

As of Django 1.4, session cookies are always sent with the HttpOnly flag, which provides some additional protection from cross-site scripting attacks by denying client-side scripts access to the session cookie.

Though not directly a security issue in Django, it has been reported that the Django 1.4 documentation incorrectly described this change, by claiming that this was now the default for all cookies set by the HttpResponse.set_cookie() method.

The Django documentation has been updated to reflect that this only applies to the session cookie. Users of Django are encouraged to review their use of set_cookie() to ensure that the HttpOnly flag is being set or unset appropriately.

Affected versions

The Host header issue described above is present in the following versions of Django:

The HttpOnly cookie documentation issue is present in the following versions of Django:


Patches have been applied to Django's development master branch, and to the 1.4 and 1.3 release branches, which resolve the issues described above. The patches may be obtained directly from the following changesets:

The following new releases have been issued:

As Django's development branch is currently in a pre-alpha state, users are strongly advised not to be running production deployments from it; if you are currently doing so, however, you are urged to upgrade imediately to the latest HEAD, which contains the above patches.


The Host header issue was reported by James Kettle. The HttpOnly cookie documentation issue was reported by Preston Holmes, who is now a committer on Django.

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 information.

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