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Mozilla JavaScript security bypass vulnerability

Vulnerability Note VU#968814

Original Release Date: 2006-04-17 | Last Revised: 2006-05-17


Mozilla products fail to properly enforce security restrictions in JavaScript. This vulnerability may allow a remote, unauthenticated attacker to execute arbitrary code.


According to Mozilla Foundation Security Advisory 2006-28:

The security check in js_ValueToFunctionObject() can be bypassed by clever use of setTimeout() and the new Firefox 1.5 array method ForEach. shutdown demonstrated how to leverage this into a privilege escalation vulnerability that would allow the installation of malware.
Note that JavaScript must be enabled in order for this vulnerability to exist. JavaScript is enabled by default in the Firefox and Mozilla web browsers, but not in the Mozilla's mail client or Thunderbird. Exploitation can occur by accessing a specially crafted web page with Firefox. If JavaScript is enabled within Mozilla's mail client or Thunderbird, then this issue may be exploitable by opening a specially crafted email.


A remote, unauthenticated attacker may be able to execute arbitrary code on a vulnerable system.


This issue is fixed in Firefox, Thunderbird, and SeaMonkey 1.0.1.

Disable JavaScript

For instructions on how to disable JavaScript in Firefox, please refer to the Firefox section of the Securing Your Web Browser document.

Vendor Information


Mozilla, Inc. Affected

Updated:  April 17, 2006



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.


Refer to

If you have feedback, comments, or additional information about this vulnerability, please send us email.

Red Hat, Inc. Not Affected

Updated:  May 17, 2006


Not Affected

Vendor Statement

This issue only affected version 1.5 of Firefox and Thunderbird. Red Hat Enterprise Linux 4 shipped with Firefox and Thunderbird versions prior to 1.5 and are not vulnerable to this issue. Other releases of Red Hat Enterprise Linux did not ship with Firefox or Thunderbird and were therefore not vulnerable to this issue.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

CVSS Metrics

Group Score Vector



This vulnerability was reported in Mozilla Foundation Security Advisory 2006-28.

This document was written by Jeff Gennari.

Other Information

CVE IDs: CVE-2006-1726
Severity Metric: 20.45
Date Public: 2006-04-13
Date First Published: 2006-04-17
Date Last Updated: 2006-05-17 12:47 UTC
Document Revision: 24

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