| From the Django advisory:
As of the 1.2 release, the core Django framework includes a system, enabled by default, for detecting and preventing cross-site request forgery (CSRF) attacks against Django-powered applications. Previous Django releases provided a different, optionally-enabled system for the same purpose.
The Django 1.2 CSRF protection system involves the generation of a random token, inserted as a hidden field in outgoing forms. The same value is also set in a cookie, and the cookie value and form value are compared on submission.
The provided template tag for inserting the CSRF token into forms -- {% csrf_token %} -- explicitly trusts the cookie value, and displays it as-is. Thus, an attacker who is able to tamper with the value of the CSRF cookie can cause arbitrary content to be inserted, unescaped, into the outgoing HTML of the form, enabling cross-site scripting (XSS) attacks.
This issue was first reported via a public ticket in Django's Trac instance; while being triaged it was then independently reported, with broader description, by Jeff Balogh of Mozilla. | 