May 14, 2014
Django 1.4.13 fixes two security issues in 1.4.12.
In certain situations, Django may allow caches to store private data related to a particular session and then serve that data to requests with a different session, or no session at all. This can lead to information disclosure and can be a vector for cache poisoning.
When using Django sessions, Django will set a
Vary: Cookie header to
ensure caches do not serve cached data to requests from other sessions.
However, older versions of Internet Explorer (most likely only Internet
Explorer 6, and Internet Explorer 7 if run on Windows XP or Windows Server
2003) are unable to handle the
Vary header in combination with many content
types. Therefore, Django would remove the header if the request was made by
To remedy this, the special behavior for these older Internet Explorer versions
has been removed, and the
Vary header is no longer stripped from the response.
In addition, modifications to the
Cache-Control header for all Internet Explorer
requests with a
Content-Disposition header have also been removed as they
were found to have similar issues.
The validation for redirects did not correctly validate some malformed URLs, which are accepted by some browsers. This allows a user to be redirected to an unsafe URL unexpectedly.
Django relies on user input in some cases (e.g.
i18n) to redirect the user to an “on success” URL.
The security checks for these redirects (namely
django.utils.http.is_safe_url()) did not correctly validate some malformed
URLs, such as
http:\\\\\\djangoproject.com, which are accepted by some
browsers with more liberal URL parsing.
To remedy this, the validation in
is_safe_url() has been tightened to be able
to handle and correctly validate these malformed URLs.