Security researcher Herre reported a use-after-free vulnerability when a Content Policy modifies the Document Object Model to remove a DOM object, which is then used afterwards due to an error in microtask implementation. This leads to an exploitable crash.

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/2015/mfsa2015-63.html


Acknowledgements:

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