diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 961657ec619..46a6aa9ec21 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -1465,6 +1465,7 @@ make_flags(void)
 #undef SetFlag
 
     if (PyErr_Occurred()) {
+        Py_DECREF(seq);
         return NULL;
     }
     return seq;