Microsoft Internet Explorer 8 and 9 does not properly handle objects in memory, which allows user-assisted remote attackers to execute arbitrary code by accessing a deleted object, aka "Developer Toolbar Remote Code Execution Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A15425
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-037