Enigmail 1.7.x before 1.7.2 sends emails in plaintext when encryption is enabled and only BCC recipients are specified, which allows remote attackers to obtain sensitive information by sniffing the network.
lists.opensuse.org/opensuse-updates/2014-09/msg00004.html
lists.opensuse.org/opensuse-updates/2014-09/msg00008.html
secunia.com/advisories/60779
secunia.com/advisories/60887
secunia.com/advisories/61854
sourceforge.net/p/enigmail/bugs/294/
sourceforge.net/p/enigmail/forum/support/thread/3e7268a4/
www.openwall.com/lists/oss-security/2014/08/18/2
www.openwall.com/lists/oss-security/2014/08/22/1
advisories.mageia.org/MGASA-2014-0421.html
security.gentoo.org/glsa/201504-01