Security researcher Sachin Shinde reported that moving certain XBL-backed nodes from a document into the replacement document created by document.open() can cause a JavaScript compartment mismatch which can often lead to exploitable conditions.

Starting with Firefox 20 this condition was turned into a run-time assertion that would crash the browser in an unexploitable way, and in Firefox 24 the underlying cause was fixed.

In general this flaw cannot be exploited through email in the Thunderbird product because scripting is disabled, but is potentially a risk in browser or browser-like contexts.


External Reference:

http://www.mozilla.org/security/announce/2013/mfsa2013-88.html


Acknowledgements:

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