Cisco ubr900 series routers that conform to the Data-over-Cable Service Interface Specifications (DOCSIS) standard must ship without SNMP access restrictions, which can allow remote attackers to read and write information to the MIB using arbitrary community strings.
http://www.securityfocus.com/bid/3758
http://www.iss.net/security_center/static/7806.php
http://archives.neohapsis.com/archives/vulnwatch/2002-q1/0002.html
http://archives.neohapsis.com/archives/bugtraq/2001-12/0297.html