An unspecified vulnerabilities were found in Microsoft Silverlight. By exploiting these vulnerabilities malicious users can execute arbitrary code. These vulnerabilities can be exploited remotely via a specially designed font data.

Microsoft Silverlight 4 earlier than 4.1.10329
Microsoft Silverlight 5 earlier than 5.1.10411

Install necessary updates from the KB section, that are listed in your Windows Update (Windows Update usually can be accessed from the Control Panel)

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