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Microsoft Hyperlink Object Library buffer overflow

Vulnerability Note VU#820427

Original Release Date: 2005-02-08 | Last Revised: 2005-02-08


A buffer overflow exists in the Microsoft Windows system library used when handling hyperlinks. All currently supported versions of Microsoft Windows are affected.


An unchecked buffer in the Microsoft Object Library is vulnerable to attack when malformed hyperlinks are handled. Such handling occurs most often when a user clicks on a hyperlink in a browser or in HTML-rendered email.

The Object Library is a dynamic application interface library used by Windows programs to manage hyperlink objects. Hyperlink objects are any COM objects (including ActiveX) that implement the IHlink interface.


An attacker could execute arbitrary code of their choosing on the system running the vulnerable version of Windows. Upon successful exploitation, the malicious code would be executed with the privileges of the user being attacked.


Apply a patch from the vendor

Microsoft has published Microsoft Security Bulletin MS05-015 in response to this issue. Users are encouraged to review this bulletin and apply the patches it refers to.


As noted in Microsoft Security Bulletin MS05-015:

Read e-mail messages in plain text format if you are using Outlook 2002 or a later version, or Outlook Express 6 SP1 or a later version, to help protect yourself from the HTML e-mail attack vector.

Note that an email-borne attack vector requires a click event on a hyperlink to occur.

Vendor Information


Microsoft Corporation Affected

Updated:  February 08, 2005



Vendor Statement

Please see Microsoft Security Bulletin MS05-015 at

Vendor Information

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


US-CERT has no additional comments at this time.

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

CVSS Metrics

Group Score Vector



Microsoft has acknowledged Anna Hollingzworth as the discoverer of this vulnerability.

This document was written by Jeffrey S Havrilla.

Other Information

CVE IDs: CVE-2005-0057
Severity Metric: 55.28
Date Public: 2005-02-08
Date First Published: 2005-02-08
Date Last Updated: 2005-02-08 22:39 UTC
Document Revision: 11

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