Security researcher Scott Bell used the Address Sanitizer tool to discover a use-after-free when using a <select> element in a form after it has been destroyed. This could lead to a potentially 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/2013/mfsa2013-81.html Acknowledgements: Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Scott Bell 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