Vulnerability Note VU#968814

Mozilla JavaScript security bypass vulnerability

Original Release date: 17 Apr 2006 | Last revised: 17 May 2006


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.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Mozilla, Inc.Affected-17 Apr 2006
Red Hat, Inc.Not Affected-17 May 2006
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 in Mozilla Foundation Security Advisory 2006-28.

This document was written by Jeff Gennari.

Other Information

  • CVE IDs: CVE-2006-1726
  • Date Public: 13 Apr 2006
  • Date First Published: 17 Apr 2006
  • Date Last Updated: 17 May 2006
  • Severity Metric: 20.45
  • Document Revision: 23


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