Unknown vulnerability in Cisco Catalyst 7.5(1) allows local users to bypass authentication and gain access to the enable mode without a password.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2003-0211
http://www.kb.cert.org/vuls/id/443257
http://www.cisco.com/warp/public/707/cisco-sa-20030424-catos.shtml.