The HP Embedded Web Server (EWS) on HP LaserJet Printers, Edgeline Printers, and Digital Senders has no management password by default, which makes it easier for remote attackers to obtain access.
http://www.vupen.com/english/advisories/2009/0754
http://www.securityfocus.com/archive/1/501884/100/0/threaded
http://www.louhinetworks.fi/advisory/HP_20090317.txt
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c01684566