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Mozilla Foundation Security Advisory 2011-53

Title: Miscellaneous memory safety hazards (rv:9.0)
Impact: Critical
Announced: December 20, 2011
Reporter: Mozilla developers and community
Products: Firefox, Thunderbird, SeaMonkey

Fixed in: Firefox 9.0
  Thunderbird 9.0
  SeaMonkey 2.6


Mozilla developers identified and fixed several memory safety bugs in the browser engine used in Firefox and other Mozilla-based products. Some of these bugs 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.

In general these flaws cannot be exploited through email in the Thunderbird and SeaMonkey products because scripting is disabled, but are potentially a risk in browser or browser-like contexts in those products.

These vulnerabilities did not affect the older browser engine used prior to Firefox 4.


Alexandre Poirot, Chris Blizzard, Kyle Huey, Scoobidiver, Christian Holler, David Baron, Gary Kwong, Jim Blandy, Bob Clary, Jesse Ruderman, Marcia Knous, and Rober Longson reported memory safety problems that were fixed in Firefox 9.