diff --git a/Modules/_cursesmodule.c b/Modules/_cursesmodule.c
index f2afd60b1fc9a7..6e2522def97e26 100644
--- a/Modules/_cursesmodule.c
+++ b/Modules/_cursesmodule.c
@@ -2410,6 +2410,7 @@ _curses_window_insnstr_impl(PyCursesWindowObject *self, int group_left_1,
         attr_old = getattrs(self->win);
         if (curses_wattrset(self, attr, "insnstr") < 0) {
             curses_release_wstr(strtype, wstr);
+            Py_XDECREF(bytesobj);
             return NULL;
         }
     }