python-django - security update

Denial-of-service possibility in logout() view by filling session store

Previously, a session could be created when anonymously accessing the
django.contrib.auth.views.logout view (provided it wasn’t decorated with
django.contrib.auth.decorators.login_required as done in the admin). This
could allow an attacker to easily create many new session records by
sending repeated requests, potentially filling up the session store or
causing other users’ session records to be evicted.

The django.contrib.sessions.middleware.SessionMiddleware has been modified
to no longer create empty session records.

This portion of the fix has been assigned CVE-2015-5963.

Additionally, the contrib.sessions.backends.base.SessionBase.flush() and
cache_db.SessionStore.flush() methods have been modified to avoid creating
a new empty session. Maintainers of third-party session backends should
check if the same vulnerability is present in their backend and correct it
if so.

This portion of the fix has been assigned CVE-2015-5964.

We recommend that you upgrade your python-django packages.