Security Update, February 22, 2001

This update resolves the "Malformed vCard" security vulnerability in Outlook and Outlook Express. This vulnerability exists because the component in Outlook and Outlook Express that processes the vCard (virtual business card) has an unchecked buffer (a temporary data storage area without a string length limit). A malicious user can exploit this vulnerability by creating a vCard that contains specially malformed data, and sending it to another user. When the recipient opens the vCard, the data overruns the buffer. This causes the e-mail program to stop functioning until it is restarted. In a more serious case, a malicious user could exploit the unchecked buffer to run unauthorized on the other user's computer. Download now to ensure that your e-mail service processes vCards correctly.

For more information about this vulnerability, please read Microsoft Security Bulletin MS01-012.

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System Requirements

This update applies to:

•	Internet Explorer 5.01 Service Pack 1.
•	Internet Explorer 5.5 Service Pack 1.

Note: Because this vulnerability exists in a component of Outlook Express, which ships as a part of Internet Explorer, the update version you download is dependent upon whether you have Internet Explorer 5.5 Service Pack 1 or Internet Explorer 5.01 Service Pack 1.

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How to download and install

Select your language from the download box on the right.

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How to use

Restart your computer to complete the installation.

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How to uninstall

Uninstall is not available.

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