[1.9.x] Fixed CVE-2016-9014 -- Validated Host header when DEBUG=True.

This is a security fix.

1 files changed, 7 insertions, 3 deletions

diff --git a/docs/ref/settings.txt b/docs/ref/settings.txt
index 63aca2e978..ba5ae2e351 100644
--- a/docs/ref/settings.txt
+++ b/docs/ref/settings.txt
@@ -90,14 +90,18 @@ If the ``Host`` header (or ``X-Forwarded-Host`` if
 list, the :meth:`django.http.HttpRequest.get_host()` method will raise
 :exc:`~django.core.exceptions.SuspiciousOperation`.
 
-When :setting:`DEBUG` is ``True`` or when running tests, host validation is
-disabled; any host will be accepted. Thus it's usually only necessary to set it
-in production.
+When :setting:`DEBUG` is ``True`` and ``ALLOWED_HOSTS`` is empty, the host
+is validated against ``['localhost', '127.0.0.1', '[::1]']``.
 
 This validation only applies via :meth:`~django.http.HttpRequest.get_host()`;
 if your code accesses the ``Host`` header directly from ``request.META`` you
 are bypassing this security protection.
 
+.. versionchanged:: 1.9.11
+
+    In older versions, ``ALLOWED_HOSTS`` wasn't checked if ``DEBUG=True``.
+    This was also changed in Django 1.8.16 to prevent a DNS rebinding attack.
+
 .. setting:: ALLOWED_INCLUDE_ROOTS
 
 ALLOWED_INCLUDE_ROOTS