This security update resolves a privately reported vulnerability in Microsoft Office. The vulnerability could allow remote code execution if a user opens a specially crafted Excel file. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Installing and configuring Office File Validation (OFV) to prevent the opening of suspicious files blocks the attack vectors for exploiting the vulnerabilities described in CVE-2011-3403.