Microsoft Internet Explorer 7, when XHTML strict mode is used, allows remote attackers to execute arbitrary code via the zoom style directive in conjunction with unspecified other directives in a malformed Cascading Style Sheets (CSS) stylesheet in a crafted HTML document, aka "CSS Memory Corruption Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6081
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-002
http://www.zerodayinitiative.com/advisories/ZDI-09-012/