Security researcher regenrecht reported, via TippingPoint's Zero Day Initiative, a garbage collection flaw in Javascript Proxy objects. This can lead to a use-after-free leading to arbitrary code execution.

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/mfsa2013-19.html


Acknowledgements:

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

Statement:

Not Vulnerable. This issue does not affect the version of firefox and thunderbird as shipped with Red Hat Enterprise Linux 5 and 6