Yahoo! Messenger AudioConf ActiveX Control buffer overflow vulnerability

ID VU:388377
Type cert
Reporter CERT
Modified 2007-04-10T20:39:00



The Yahoo! Messenger AudioConf ActiveX control contains a buffer overflow, which could allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.


Yahoo! Messenger is an instant messaging application. Yahoo! Messenger includes several ActiveX controls. The AudioConf ActiveX control, which is provided by yacscom.dll, contains a buffer overflow 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

As specified in the Yahoo! Security Update, this issue is addressed in versions of Yahoo Messenger from March 13, 2007 or later. Version or higher of yacscom.dll contains the fix.

Disable the YMailAttach ActiveX control in Internet Explorer

The Yahoo! AudioConf 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.

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


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Yahoo, Inc. Affected

Updated: April 09, 2007



Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

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


See <;_ylt=AkQgcpun6x0v49V3Uxj7PSnlLdMF?id=031207> for more details.

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

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Thanks to Yahoo and ZDI for information that was used in this report. Yahoo credits ZDI for reporting this vulnerability.

This document was written by Ryan Giobbi.

Other Information

CVE IDs: | CVE-2007-1680
Severity Metric: | 10.21
Date Public: | 2007-04-03
Date First Published: | 2007-04-09
Date Last Updated: | 2007-04-10 20:39 UTC
Document Revision: | 12