Unspecified vulnerability in Mac OS X before 10.4.6, when running on an Intel-based computer, allows attackers with physical access to bypass the firmware password and log on in Single User Mode via unspecified vectors.
https://exchange.xforce.ibmcloud.com/vulnerabilities/25620
http://www.vupen.com/english/advisories/2006/1215
http://www.securityfocus.com/bid/17364
http://securitytracker.com/id?1015859