Mozilla community member Ezra Pool reported a potentially exploitable crash on extremely large pages. This was caused when a cycle collected image object was released on the wrong thread during decoding, creating a race condition. In general this flaw cannot be exploited through email in the Thunderbird and Seamonkey products because scripting is disabled, but is potentially a risk in browser or browser-like contexts. External Reference: http://www.mozilla.org/security/announce/2013/mfsa2013-97.html Acknowledgements: Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Ezra Pool as the original reporter. Statement: This issue does not affect the version of firefox and thunderbird as shipped with Red Hat Enterprise Linux 5 and 6