Microsoft released security bulletin MS13-038 and update KB2847204 on May 14, 2013, to address the publicly disclosed, actively exploited Internet Explorer use-after-free vulnerability CVE-2013-1347. Specially crafted web content could trigger remote code execution with the current user's privileges. Microsoft confirmed attacks targeting Internet Explorer 8 and rated the update Critical for affected Windows clients and Moderate for Windows servers. Internet Explorer 9 received a defense-in-depth update because its default configuration blocked known attack vectors.
The patch corrects Internet Explorer's handling of objects in memory. Microsoft recommended immediate installation alongside cumulative update MS13-037 to avoid compatibility issues. Temporary mitigations included the MSHTML Shim workaround, scripting restrictions, Internet Explorer Enhanced Security Configuration, and the Enhanced Mitigation Experience Toolkit (EMET). Microsoft's Windows Update Standalone Installer documentation provides supporting guidance for deploying standalone Windows update packages.

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Microsoft published MS13-038 and released KB2847204, correcting Internet Explorer's handling of objects in memory. Microsoft confirmed awareness of attacks attempting to exploit Internet Explorer 8 and recommended immediate installation alongside cumulative update MS13-037.
Microsoft provided an automated Fix it solution implementing the MSHTML Shim workaround to prevent exploitation through known attack vectors. Customers who applied it could leave it installed while deploying the subsequent security update.
Microsoft first described the publicly disclosed vulnerability CVE-2013-1347 in Security Advisory 2847140. The use-after-free flaw could allow arbitrary code execution with the current Internet Explorer user's privileges.
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