Vulnerability Note VU#866300

Mozilla Firefox designMode deleted object reference

Original Release date: 02 May 2006 | Last revised: 18 May 2006


Mozilla Firefox contains a deleted object reference vulnerability. This may allow a remote attacker to execute arbitrary code.


Mozilla Firefox contains a vulnerability that causes a deleted object to be referenced when designMode is set to "on." When Firefox attempts to use this deleted object, the browser can crash. It may be possible to execute arbitrary code by using references to deleted objects.


A remote, unauthenticated attacker may be able to execute arbitrary code with the privileges of the user running Firefox.


Apply an update

Update to Firefox, as specified in Mozilla Foundation Security Advisory 2006-30.

Disable scripting

This vulnerability can be mitigated by disabling JavaScript.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Mozilla, Inc.Affected-02 May 2006
Red Hat, Inc.Not Affected-18 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 publicly disclosed by splices. Mozilla also credits Martijn Wargers and Nick Mott.

This document was written by Will Dormann.

Other Information

  • CVE IDs: CVE-2006-1993
  • Date Public: 24 Apr 2006
  • Date First Published: 02 May 2006
  • Date Last Updated: 18 May 2006
  • Severity Metric: 7.87
  • Document Revision: 16


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