The PL/SQL module for the Oracle HTTP Server in Oracle Application Server 10g, when using the WE8ISO8859P1 character set, does not perform character conversions properly, which allows remote attackers to bypass access restrictions for certain procedures via an encoded URL with "%FF" encoded sequences that are improperly converted to "Y" characters.
https://exchange.xforce.ibmcloud.com/vulnerabilities/18657
http://www.us-cert.gov/cas/techalerts/TA04-245A.html
http://www.securityfocus.com/bid/10871
http://www.oracle.com/technology/deploy/security/pdf/2004alert68.pdf
http://www.ngssoftware.com/advisories/oracle23122004G.txt
http://www.kb.cert.org/vuls/id/435974
http://sunsolve.sun.com/search/document.do?assetkey=1-26-101782-1