Oracle Database Server 8.1.7.4 through 9.2.0.4 allows local users to execute commands with additional privileges via the ctxsys.driload package, which is publicly accessible.
http://www.securityfocus.com/bid/11099
http://www.kb.cert.org/vuls/id/316206
http://www.idefense.com/application/poi/display?id=136&type=vulnerabilities&flashstatus=true