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Mozilla Foundation Security Advisory 2006-44

Title: Code execution through deleted frame reference
Impact: Critical
Announced: July 25, 2006
Reporter: Thilo Girmann
Products: Firefox 1.5, SeaMonkey 1.0

Fixed in: Firefox
  SeaMonkey 1.0.3


Thilo Girmann discovered that in certain circumstances a JavaScript reference to a frame or window was not properly cleared when the referenced content went away, and he demonstrated that this pointer to a deleted object could be used to execute native code supplied by the attacker.

This vulnerability was introduced during Firefox 1.5 development, it does not affect Firefox 1.0 or Mozilla Suite 1.7

Thunderbird shares the browser engine with Firefox and would be vulnerable if JavaScript were to be enabled in mail. This is not the default setting and we strongly discourage users from enabling JavaScript in mail.


Disable JavaScript until you can upgrade to a fixed version. Do not enable JavaScript in mail clients such as Thunderbird.


Exploit details withheld until after the active update period.