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Mozilla WOFF decoder integer overflow

Vulnerability Note VU#964549

Original Release Date: 2010-03-23 | Last Revised: 2010-07-28


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:

    Vendor Information

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


    Mozilla Affected

    Notified:  February 19, 2010 Updated: March 23, 2010

    Statement Date:   March 22, 2010



    Vendor Statement

    We have not received a statement from the vendor.

    Vendor Information

    Mozilla has published Mozilla Foundation Security Advisory 2010-08 in response to this issue. Users are encouraged to review this advisory and install the updated software it describes.

    Vendor References

    CVSS Metrics

    Group Score Vector



    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
    Severity Metric: 16.88
    Date Public: 2010-03-17
    Date First Published: 2010-03-23
    Date Last Updated: 2010-07-28 17:02 UTC
    Document Revision: 17

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