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CERT Coordination Center

Skype VCARD handling routine contains a buffer overflow

Vulnerability Note VU#668193

Original Release Date: 2005-10-26 | Last Revised: 2005-12-19


A buffer overflow in the way Skype handles imported VCARDs may allow a remote attacker to execute code on a vulnerable system.


Skype software provides telephone service over IP networks. Skype fails to properly validate imported VCARDs, allowing a buffer overflow to occur. The buffer overflow may stem from an input validation error in the Delphi routine SysUtils.WideFmtStr(...).

For more information, please see Skype Security Bulletin SKYPE-SB/2005-002 and Delphi Bug Report 4744.


A remote attacker may be able to execute arbitrary code if they can persuade a user to import a specially crafted VCARD with a Skype-specific URI with a vulnerable Skype installation.


Upgrade Skype

Please see Skype Security Bulletin SKYPE-SB/2005-002 for a list of fixed Skype versions.

Do not import VCARDs from untrusted sources

Exploitation occurs by importing a specially crafted VCARD. By only accessing a VCARDs from trusted or known sources, the chances of exploitation are reduced.

Vendor Information


Skype Technologies Affected

Updated:  October 26, 2005



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.


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This vulnerability was reported by SKY-CERT. SKY-CERT credits Mark Rowe of Pentest Limited with providing information regarding this issue.

This document was written by Jeff Gennari.

Other Information

CVE IDs: CVE-2005-3265
Severity Metric: 10.13
Date Public: 2005-10-25
Date First Published: 2005-10-26
Date Last Updated: 2005-12-19 14:34 UTC
Document Revision: 11

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