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Mozilla Foundation Security Advisory 2006-67

Title: Running Script can be recompiled
Impact: Critical
Announced: November 7, 2006
Reporter: shutdown
Products: Firefox, Thunderbird, SeaMonkey

Fixed in: Firefox
  SeaMonkey 1.0.6


shutdown demonstrated that it was possible to modify a Script object while it was executing, potentially leading to the execution of arbitrary JavaScript bytecode.

Thunderbird shares the browser engine with Firefox and could 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.

The Firefox 2.0 release is not affected by this vulnerability.


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