I have reviewed this document as part of the security directorate's  ongoing
effort to review all IETF documents being processed by the  IESG.  These
comments were written primarily for the benefit of the  security area
directors.  Document editors and WG chairs should treat these comments just
like any other last call comments.

This document specifies how to add extensions to Babel routing protocol 
so that it can route IPv4 packets over network core without IPv4 addresses.

Its security considerations section do mention the fact that this feature 
might invalidate the assumptions made by the network administrators, and 
suggest packet filters to mitigate this issue. I think the current security
considerations section covers issues caused by this extension.