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Microsoft Internet Explorer iepeers.dll use-after-free vulnerability

Vulnerability Note VU#744549

Original Release Date: 2010-03-09 | Last Revised: 2010-03-30


Microsoft Internet Explorer contains a use-after-free vulnerability in the iepeers.dll file, which may allow a remote, unauthenticated attacker to execute arbitrary code.


Microsoft Internet Explorer provides support for Web Folders and printing through the use of the iepeers.dll component. According to Microsoft Security Advisory (981374), the iepeers.dll contains a vulnerability in the use of a pointer after an object is freed. Microsoft reports that the vulnerability, which affects Internet Explorer 6 and 7, has been reported publicly.

Exploit code for this vulnerability is publicly available. This vulnerability is currently being exploited in the wild.


By convincing a user to load a specially crafted HTML document or Microsoft Office document, a remote, unauthenticated attacker may be able to execute arbitrary code or cause a denial-of-service condition.


Apply an update
This issue is addressed in Microsoft Security Bulletin MS10-018, which modifies the way Internet Explorer handles objects in memory.

Enable Data Execution Prevention (DEP) on Internet Explorer 6 or Internet Explorer 7

Microsoft has published more information on DEP as a mitigation for this vulnerability. DEP should not be treated as a complete workaround, but DEP can mitigate the execution of attacker-supplied code in some cases. Microsoft has published detailed technical information about DEP in Security Research & Defense blog posts "Understanding DEP as a mitigation technology" part 1 and part 2. Use of DEP should be considered in conjunction with other mitigations described in this document.

Set the Internet zone security setting to "High"

Setting the Internet zone security setting to "High" will result in the user being prompted before running ActiveX controls and Active Scripting, which may reduce the risk of certain attack vectors.

Disable Active Scripting

Disabling Active Scripting will prevent Active Scripting from running, which may reduce the risk of certain attack vectors.

Vendor Information


Microsoft Corporation Affected

Updated:  March 09, 2010



Vendor Statement

We have not received a statement from the vendor.

Vendor Information

Please see Microsoft Security Advisory (981374).

Vendor References

CVSS Metrics

Group Score Vector



Thanks to Microsoft for reporting this vulnerability.

This document was written by Will Dormann.

Other Information

CVE IDs: CVE-2010-0806
Severity Metric: 28.55
Date Public: 2010-03-09
Date First Published: 2010-03-09
Date Last Updated: 2010-03-30 21:56 UTC
Document Revision: 18

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