[4.2.x] Fixed CVE-2026-1312 -- Protected order_by() from SQL injection via aliases with periods.

Before, `order_by()` treated a period in a field name as a sign that it
was requested via `.extra(order_by=...)` and thus should be passed
through as raw table and column names, even if `extra()` was not used.
Since periods are permitted in aliases, this meant user-controlled
aliases could force the `order_by()` clause to resolve to a raw table
and column pair instead of the actual target field for the alias.

In practice, only `FilteredRelation` was affected, as the other
expressions we tested, e.g. `F`, aggressively optimize away the ordering
expressions into ordinal positions, e.g. ORDER BY 2, instead of ORDER BY
"table".column.

Thanks Solomon Kebede for the report, and Simon Charette and Jake Howard
for reviews.

Backport of 69065ca869b0970dff8fdd8fafb390bf8b3bf222 from main.

1 files changed, 10 insertions, 0 deletions

diff --git a/docs/releases/4.2.28.txt b/docs/releases/4.2.28.txt
index fa6b1f19bd..a618474f0f 100644
--- a/docs/releases/4.2.28.txt
+++ b/docs/releases/4.2.28.txt
@@ -70,3 +70,13 @@ expansion, as the ``**kwargs`` passed to :meth:`.QuerySet.annotate`,
 
 This issue has severity "high" according to the :ref:`Django security policy
 <security-disclosure>`.
+
+CVE-2026-1312: Potential SQL injection via ``QuerySet.order_by`` and ``FilteredRelation``
+=========================================================================================
+
+:meth:`.QuerySet.order_by` was subject to SQL injection in column aliases
+containing periods when the same alias was, using a suitably crafted
+dictionary, with dictionary expansion, used in :class:`.FilteredRelation`.
+
+This issue has severity "high" according to the :ref:`Django security policy
+<security-disclosure>`.