Severity Rating: Moderate - Revision Note: V1.1 (August 10, 2011): Revised the Server Core installation not affected notation for Windows Server 2008 and Windows Server 2008 R2 to clarify that the update will still be offered to systems installed using the Server Core installation option.Summary: This security update resolves a publicly disclosed vulnerability in Microsoft Windows. The vulnerability could allow denial of service if a user visits a network share (or visits a Web site that points to a network share) containing a specially crafted file. In all cases, however, an attacker would have no way to force a user to visit such a network share or Web site. Instead, an attacker would have to convince a user to do so, typically by getting the user to click a link in an e-mail message or Instant Messenger message.

Severity Rating: Important - Revision Note: V1.1 (August 10, 2011): Corrected the restart requirements for the update on all affected operating systems.Summary: This security update resolves a privately reported vulnerability in Microsoft Windows. The vulnerability could allow remote code execution if a user opens a legitimate Excel file (such as a .xlsx file) that is located in the same network directory as a specially crafted library 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.

Severity Rating: Important - Revision Note: V1.1 (August 10, 2011): Removed two erroneous workarounds in this bulletin's vulnerability section for CVE-2011-1276. This is an informational change only. Summary: This security update resolves eight privately reported vulnerabilities in Microsoft Office. The vulnerabilities could allow remote code execution if a user opens a specially crafted Excel file. An attacker who successfully exploited any of these vulnerabilities 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-2011-1272, CVE-2011-1273, and CVE-2011-1279. See the section, Frequently Asked Questions (FAQ) Related to This Security Update, for more information about how the Office File Validation feature can be configured to block the attack vectors. Microsoft Excel 2010 is only affected by CVE-2011-1273 described in this bulletin. The automated Microsoft Fix it solution, "Disable Edit in Protected View for Excel 2010," available in Microsoft Knowledge Base Article 2501584, blocks the attack vectors for exploiting CVE-2011-1273.