http://www.mozilla.org/security/announce/2012/mfsa2012-01.html

Mozilla Foundation Security Advisory 2012-01

Title: Miscellaneous memory safety hazards (rv:10.0/ 1.9.2.26)
Impact: Critical
Announced: January 31, 2012
Reporter: Mozilla developers and community
Products: Firefox, Thunderbird, SeaMonkey

Fixed in: Firefox 10.0
Fixed in: Firefox 3.6.26
Thunderbird 10.0
Thunderbird 3.1.18
SeaMonkey 2.7
Description

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.

References

Ben Hawkes, Christian Holler, Honza Bombas, Jason Orendorff, Jesse Ruderman, Jan Odvarko, Peter Van Der Beken, and Bill McCloskey reported memory safety problems that were fixed in Firefox 10.

Memory safety bugs fixed in Firefox 10
CVE-2012-0443
Jesse Ruderman and Bob Clary reported memory safety problems that were fixed in both Firefox 10 and Firefox 3.6.26.

Memory safety bugs fixed in Firefox 10 and Firefox 3.6.26
CVE-2012-0442