Vulnerability Note VU#964549

Mozilla WOFF decoder integer overflow

Original Release date: 23 Mar 2010 | Last revised: 28 Jul 2010


An integer overflow in the Mozilla Web Open Fonts Format (WOFF) decoder may allow a remote attacker to execute code on an affected system.


The Web Open Fonts Format (WOFF) is a simple compressed file format for fonts. Mozilla introduced support for WOFF in the 1.9.2 branch of the base software, which is used by Firefox versions 3.6 and later.

An integer overflow error exists in the way the WOFF decoder handles the size of tables specified in the font file. This error could result in a buffer overflow vulnerability on a subsequent memory allocation. A remote attacker who is able to supply a malicious WOFF file could exploit this vulnerability.


A remote, unauthenticated attack may be able to execute arbitrary code with the privileges of the victim user.



Mozilla has addressed this issue in Firefox version 3.6.2. Users are encouraged to upgrade to this version of the browser.

Disable downloading of remote fonts

By performing the following steps, it is possible to prevent Mozilla from retrieving and displaying remote fonts.

  1. Enter "about:config" into the browser's address bar. This will display Firefox's configuration values.
  2. Set the following value to false:

Systems Affected (Learn More)

Any Mozilla-derived product that uses the Mozilla 1.9.2 code could be affected.

VendorStatusDate NotifiedDate Updated
MozillaAffected19 Feb 201023 Mar 2010
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 to Mozilla by Evgeny Legerov of Intevydis.

This document was written by Chad R Dougherty.

Other Information

  • CVE IDs: CVE-2010-1028
  • Date Public: 17 Mar 2010
  • Date First Published: 23 Mar 2010
  • Date Last Updated: 28 Jul 2010
  • Severity Metric: 16.87
  • Document Revision: 17


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