Vulnerability Note VU#744549

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

Original Release date: 09 Mar 2010 | Last revised: 30 Mar 2010


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.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Microsoft CorporationAffected-09 Mar 2010
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A



Thanks to Microsoft for reporting this vulnerability.

This document was written by Will Dormann.

Other Information

  • CVE IDs: CVE-2010-0806
  • Date Public: 09 Mar 2010
  • Date First Published: 09 Mar 2010
  • Date Last Updated: 30 Mar 2010
  • Severity Metric: 28.55
  • Document Revision: 16


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