Vulnerability Note VU#784278

Mozilla fails to validate the DN of X.509 certificates

Original Release date: 23 Aug 2004 | Last revised: 25 Aug 2004


Mozilla fails to verify that the Distinguished Name (DN) of an X.509 certificate is unique when importing it. A denial of service occurs when Mozilla imports a specially crafted, self-signed certificate that has the same DN as an existing Certificate Authority (CA) root certificate.


Mozilla version 1.7.1 and earlier can import a self-signed certificate with the same DN as an existing CA root certificate. When this occurs, the imported certificate will override the CA root certificate. Mozilla will return an error when attempting to create a secure connection to a website whose certificate is signed by a CA root certificate that has been overridden in this manner. A remote attacker can automate exploitation of this vulnerability using the "application/x-x509-email-cert" MIME type. This will permit Mozilla to import the certificate without any user intervention.


A remote attacker could cause a denial of service against the certificate store, preventing the user from accessing SSL websites.


This issue has been resolved in the following versions:

Mozilla 1.7.2
Firefox 0.9.3
Thunderbird 0.7.3

For other Mozilla-based products, please check with your vendor for updates.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Gentoo LinuxAffected-24 Aug 2004
MozillaAffected-23 Aug 2004
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 was reported on the Mozilla Known Vulnerabilities List. Mozilla attributes this report to Marcel Boesch.

This document was written by Will Dormann.

Other Information

  • CVE IDs: CAN-2004-0758
  • Date Public: 29 Jun 2004
  • Date First Published: 23 Aug 2004
  • Date Last Updated: 25 Aug 2004
  • Severity Metric: 5.17
  • Document Revision: 12


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