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 product because scripting is disabled, but are potentially a risk in browser or browser-like contexts.
André Bargull, Scoobidiver, Bobby Holley, and Reuben Morais reported memory safety problems and crashes that affect Firefox ESR 17, and Firefox 23.
Christian Holler, Makoto Kato, Jesse Ruderman, Jason Smith, Jan de Mooij, Gary Kwong, Scoobidiver, Olli Pettay, Bobby Holley, and Bob Clary reported memory safety problems and crashes that affect Firefox 23.