Microsoft Internet Explorer 9 does not properly handle objects in memory, which allows remote attackers to execute arbitrary code by accessing an object that was not properly initialized, aka "Jscript9.dll Remote Code Execution Vulnerability."

References

• https://nvd.nist.gov/vuln/detail/CVE-2011-1998
• https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-081
• https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A13199
• http://www.securityfocus.com/bid/49963