Severity Rating: Critical - Revision Note: V1.1 (September 29, 2010): Added a link to Microsoft Knowledge Base Article 2347290 under Known Issues in the Executive Summary.

Summary: This security update resolves a publicly disclosed vulnerability in the Print Spooler service. The vulnerability could allow remote code execution if an attacker sends a specially crafted print request to a vulnerable system that has a print spooler interface exposed over RPC. By default, printers are not shared on any currently supported Windows operating system.

Severity Rating: Critical - Revision Note: V1.2 (September 29, 2010): Added a "Compatibility Flags" value to the workaround, "Temporarily prevent the Microsoft Silverlight ActiveX control from running in Internet Explorer (Method 1)."

Summary: This security update resolves two privately reported vulnerabilities in Microsoft .NET Framework and Microsoft Silverlight. The vulnerabilities could allow remote code execution on a client system if a user views a specially crafted Web page using a Web browser that can run XAML Browser Applications (XBAPs) or Silverlight applications, or if an attacker succeeds in convincing a user to run a specially crafted Microsoft .NET application. 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. The vulnerabilities could also allow remote code execution on a server system running IIS, if that server allows processing ASP.NET pages and an attacker succeeds in uploading a specially crafted ASP.NET page to that server and executing the page, as could be the case in a Web hosting scenario.