Vulnerability Note VU#687396

Mozilla products fail to properly validate JavaScript constructors

Original Release date: 27 Jul 2006 | Last revised: 09 Feb 2007


Mozilla products fail to properly validate references returned by JavaScript constructors. This vulnerability may allow a remote attacker to execute arbitrary code on a vulnerable system.


According to Mozilla Foundation Security Advisory 2006-51:

    JavaScript functions have a parent object created using the standard Object() constructor (ECMA-specified behavior) and that this constructor can be redefined by script (also ECMA-specified behavior). If the Object() constructor is changed to return a reference to a privileged object with useful properties it is possible to have attacker-supplied script executed with elevated privileges by calling the function. This could be used to install malware or take other malicious actions.

For more information and a complete list of affected products, refer to Mozilla Foundation Security Advisory 2006-51.


A remote, unauthenticated attacker may be able to execute arbitrary code on a vulnerable system. The attacker could also cause the vulnerable application to crash.


Apply an update

This vulnerability is addressed in Firefox, Thunderbird, and SeaMonkey 1.0.3, according to the Mozilla Foundation Security Update 2006-51.

Disable JavaScript

This vulnerability can be mitigated by disabling JavaScript.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Mozilla, Inc.Affected-27 Jul 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 2006-48. Mozilla credits moz_bug_r_a4 with reporting this vulnerability.

This document was written by Jeff Gennari.

Other Information

  • CVE IDs: CVE-2006-3807
  • Date Public: 25 Jul 2006
  • Date First Published: 27 Jul 2006
  • Date Last Updated: 09 Feb 2007
  • Severity Metric: 16.03
  • Document Revision: 11


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