Mozilla developer Boris Zbarsky reported reported a problem where jsval-returning quickstubs fail to wrap their return values, causing a compartment mismatch. This mismatch can cause garbage collection to occur incorrectly and lead to a potentially exploitable crash.

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. 


External Reference:

http://www.mozilla.org/security/announce/2013/mfsa2013-09.html


Acknowledgements:

Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Boris Zbarsky as the original reporter.