Disallow keyword args for exceptions.
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index 16ba5e5..28fb0c1 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -32,6 +32,9 @@
 {
     PyBaseExceptionObject *self;
 
+    if (!_PyArg_NoKeywords("BaseException", kwds))
+        return NULL;
+
     self = (PyBaseExceptionObject *)type->tp_alloc(type, 0);
     /* the dict is created on the fly in PyObject_GenericSetAttr */
     self->message = self->dict = NULL;