Mozilla Firefox before 3.5.19 and 3.6.x before 3.6.17, and SeaMonkey before 2.0.14, does not properly implement autocompletion for forms, which allows remote attackers to read form history entries via a Java applet that spoofs interaction with the autocomplete controls.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14523
http://www.mozilla.org/security/announce/2011/mfsa2011-14.html
http://www.mandriva.com/security/advisories?name=MDVSA-2011:079
http://www.debian.org/security/2011/dsa-2235
http://www.debian.org/security/2011/dsa-2228