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.
Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Gary Kwong, Christian Holler, Jesse Ruderman, Steve Fink, Bob Clary, Andrew Sutherland, and Jason Smith as the original reporters. These flaws affected Firefox 14.
Not Vulnerable. This issue does not affect the version of Firefox and Thunderbird package as shipped with Red Hat Enterprise Linux 5 and 6.