Race condition in the nsThreadManager::RegisterCurrentThread function in Mozilla Firefox before 38.0 allows remote attackers to execute arbitrary code or cause a denial of service (use-after-free and heap memory corruption) by leveraging improper Media Decoder Thread creation at the time of a shutdown.
https://security.gentoo.org/glsa/201605-06
https://bugzilla.mozilla.org/show_bug.cgi?id=988698
http://www.ubuntu.com/usn/USN-2602-1
http://www.securityfocus.com/bid/74611
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
http://www.mozilla.org/security/announce/2015/mfsa2015-53.html
http://lists.opensuse.org/opensuse-updates/2015-05/msg00036.html