[1.6.x] Fixed an infinite loop possibility in strip_tags().

This is a security fix; disclosure to follow shortly.

1 files changed, 17 insertions, 0 deletions

diff --git a/docs/releases/1.6.11.txt b/docs/releases/1.6.11.txt
index da10a44301..a7d020c004 100644
--- a/docs/releases/1.6.11.txt
+++ b/docs/releases/1.6.11.txt
@@ -5,3 +5,20 @@ Django 1.6.11 release notes
 *March 18, 2015*
 
 Django 1.6.11 fixes two security issues in 1.6.10.
+
+Denial-of-service possibility with ``strip_tags()``
+===================================================
+
+Last year :func:`~django.utils.html.strip_tags`  was changed to work
+iteratively. The problem is that the size of the input it's processing can
+increase on each iteration which results in an infinite loop in
+``strip_tags()``. This issue only affects versions of Python that haven't
+received  `a bugfix in HTMLParser <http://bugs.python.org/issue20288>`_; namely
+Python < 2.7.7 and 3.3.5. Some operating system vendors have also backported
+the fix for the Python bug into their packages of earlier versions.
+
+To remedy this issue, ``strip_tags()`` will now return the original input if
+it detects the length of the string it's processing increases. Remember that
+absolutely NO guarantee is provided about the results of ``strip_tags()`` being
+HTML safe. So NEVER mark safe the result of a ``strip_tags()`` call without
+escaping it first, for example with :func:`~django.utils.html.escape`.