Vulnerability Note VU#252146

Microsoft Outlook and Microsoft Exchange TNEF decoding buffer overflow

Original Release date: 10 Jan 2006 | Last revised: 16 Jan 2006


Microsoft Outlook and Microsoft Exchange contain a buffer overflow vulnerability that may allow a remote, unauthenticated attacker to execute arbitrary code on a system running the vulnerable software.


Transport Neutral Encapsulation Format (TNEF)

TNEF is a proprietary Microsoft format for encoding rich text email messages. Microsoft Outlook and Microsoft Exchange support the use of TNEF-encoded messages.

The problem

Microsoft Outlook and Microsoft Exchange do not properly validate TNEF MIME attachments, potentially allowing a buffer overflow to occur. The overflow occurs in in the process that decodes TNEF MIME attachments. A remote attacker may be able trigger the buffer overflow by sending a specially crafted TNEF MIME attachment to a vulnerable Outlook or Exchange installation.

Note that on user workstations, exploitation may require a user to open or preview a malicious mail message in Outlook. However, on Exchange servers, this vulnerability can be exploited without human interaction.

For more information, please see Microsoft Security Bulletin MS06-003.


A remote unauthenticated attacker may be able to execute arbitrary code on a system running the vulnerable software. Microsoft Outlook can trigger the vulnerability when it opens or displays a preview for a specially crafted message. Microsoft Exchange can trigger the vulnerability when it processes a specially crafted message.


Apply a patch from your vendor
Microsoft addresses this vulnerability with the updates listed in Microsoft Security Bulletin MS06-003.


Microsoft has listed several workarounds in Microsoft Security Bulletin MS06-003, including blocking attachments with the MIME type of application/ms-tnef.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Microsoft CorporationAffected-10 Jan 2006
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



This vulnerability was reported by Microsoft, who in turn credit John Heasman and Mark Litchfield of NGS Software.

This document was written by Will Dormann and Jeff Gennari.

Other Information

  • CVE IDs: CVE-2006-0002
  • Date Public: 10 Jan 2006
  • Date First Published: 10 Jan 2006
  • Date Last Updated: 16 Jan 2006
  • Severity Metric: 25.51
  • Document Revision: 21


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