Use-after-free vulnerability in the CMshtmlEd::Exec function in mshtml.dll in Microsoft Internet Explorer 6 through 9 allows remote attackers to execute arbitrary code via a crafted web site, as exploited in the wild in September 2012.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A15729
http://www.us-cert.gov/cas/techalerts/TA12-265A.html
http://www.us-cert.gov/cas/techalerts/TA12-262A.html
http://www.us-cert.gov/cas/techalerts/TA12-255A.html
http://www.securityweek.com/new-internet-explorer-zero-day-being-exploited-wild
http://www.securitytracker.com/id?1027538
http://www.kb.cert.org/vuls/id/480095
http://technet.microsoft.com/security/advisory/2757760
http://eromang.zataz.com/2012/09/16/zero-day-season-is-really-not-over-yet/