Bulletin Severity Rating:Critical – This security update resolves several privately reported vulnerabilities that could allow remote code execution if a user opens a specially crafted Excel file that includes a malformed record object. An attacker who successfully exploited any of these vulnerabilities could take complete control of an affected system. An attacker could then install programs;…

Read more at: Microsoft Security Bulletins

Bulletin Severity Rating:Critical – This security update resolves several privately reported vulnerabilities that could allow remote code execution if a user opens a specially crafted Excel file that includes a malformed record object. An attacker who successfully exploited any of these vulnerabilities could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

Read more at: Microsoft Security Bulletins