The HTTP handlers in BEA WebLogic Server 9.0, 8.1 up to SP5, 7.0 up to SP6, and 6.1 up to SP7 stores the username and password in cleartext in the WebLogic Server log when access to a web application or protected JWS fails, which allows attackers to gain privileges.
https://exchange.xforce.ibmcloud.com/vulnerabilities/26463
https://euvd.enisa.europa.eu/vulnerability/EUVD-2006-2469
http://www.vupen.com/english/advisories/2006/1828
http://securitytracker.com/id?1016098