gh-149738: Fix segmentation fault bug in sqllite3

Misc/NEWS.d/next/Core_and_Builtins/2026-05-13-06-54-41.gh-issue-149738.4BLFoH.rst

@@ -0,0 +1,2 @@
+Fix a segmentation fault in :mod:`sqlite3` when ``row_factory`` is deleted
+and a query is executed afterward.

Modules/_sqlite/connection.c

@@ -549,7 +549,7 @@ pysqlite_connection_cursor_impl(pysqlite_Connection *self, PyObject *factory)
         return NULL;
     }
 
-    if (cursor && self->row_factory != Py_None) {
+    if (cursor && self->row_factory && self->row_factory != Py_None) {
         Py_INCREF(self->row_factory);
         Py_XSETREF(((pysqlite_Cursor *)cursor)->row_factory, self->row_factory);
     }