Multiple unspecified vulnerabilities in Oracle Application Express 1.5 up to 1.6.1 have unknown impact and remote attack vectors, aka Vuln# (1) APEX04, (2) APEX20, and (3) APEX21.
http://www.vupen.com/english/advisories/2006/4065
http://www.us-cert.gov/cas/techalerts/TA06-291A.html
http://www.securityfocus.com/bid/20588
http://www.securityfocus.com/archive/1/449711/100/0/threaded
http://www.red-database-security.com/advisory/oracle_cpu_oct_2006.html
http://www.oracle.com/technetwork/topics/security/cpuoct2006-095368.html