Mozilla Foundation Security Advisory 2009-24

Crashes with evidence of memory corruption (rv:

June 11, 2009
Mozilla developers and community
Firefox, SeaMonkey, Thunderbird
Fixed in
  • Firefox 3.0.11
  • SeaMonkey 1.1.17
  • Thunderbird


Mozilla developers and community members identified and fixed several stability bugs in the browser engine used in Firefox and other Mozilla-based products. Some of these crashes showed evidence of memory corruption under certain circumstances and we presume that with enough effort at least some of these could be exploited to run arbitrary code.

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 running JavaScript in mail. Without further investigation we cannot rule out the possibility that for some of these an attacker might be able to prepare memory for exploitation through some means other than JavaScript such as large images.


Disable JavaScript until a version containing these fixes can be installed.


Bob Clary, Jesse Ruderman, Alexander Sack, Bret McMillan, Tomeo Vizoso, Matt McCutchen, and Martijn Wargers reported crashes in the Firefox 3 browser engine. Boris Zbarsky also reported a method to trigger double frame construction which could lead to memory corruption.

Jesse Ruderman, Adam Hauner, and Igor Bukanov reported crashes in the Firefox 3 JavaScript engine.