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Yahoo! Webcam view utilities ActiveX control vulnerable to arbitrary code execution

Vulnerability Note VU#932217

Original Release Date: 2007-06-08 | Last Revised: 2007-06-11


The Yahoo! Webcam view utilities ActiveX control contains a stack buffer overflow, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.


Yahoo! Webcam is a component of Yahoo! Messenger that allows users to chat via webcams over a network. Yahoo! Webcam Viewer includes an ActiveX control provided by the file ywcvwr.dll . This ActiveX control contains a stack buffer overflow vulnerability in the Server property.

We are aware of publicly available exploit code for this vulnerability.


By convincing a user to view a specially crafted HTML document (e.g., a web page or an HTML email message or attachment), an attacker may be able to execute arbitrary code with the privileges of the user. The attacker could also cause Internet Explorer (or the program using the WebBrowser control) to crash.


Apply an update
This issue is addressed in Yahoo! Messenger 8.1. If you are unable to upgrade, please consider the following workarounds:

Disable the Yahoo! Messenger ActiveX control in Internet Explorer

The vulnerable ActiveX control can be disabled in Internet Explorer by setting the kill bit for the following CLSID:


More information about how to set the kill bit is available in Microsoft Support Document 240797. Alternatively, the following text can be saved as a .REG file and imported to set the kill bit for this control:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{9D39223E-AE8E-11D4-8FD3-00D0B7730277}]
"Compatibility Flags"=dword:00000400

Disable ActiveX

Disabling ActiveX controls in the Internet Zone (or any zone used by an attacker) appears to prevent exploitation of this and other ActiveX vulnerabilities. Instructions for disabling ActiveX in the Internet Zone can be found in the "Securing Your Web Browser" document. 

Vendor Information


Yahoo, Inc. Affected

Updated:  June 08, 2007



Vendor Statement

We have not received a statement from the vendor.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


Refer to Yahoo! Messenger 8.1.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

CVSS Metrics

Group Score Vector



This issue was reported by eEye Digital Security in EEYEZD-20070606.

This document was written by Chris Taschner.

Other Information

CVE IDs: None
Severity Metric: 15.53
Date Public: 2007-06-07
Date First Published: 2007-06-08
Date Last Updated: 2007-06-11 12:28 UTC
Document Revision: 13

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