The pluto IKE daemon in libreswan before 3.15 and Openswan before 2.6.45, when built with NSS, allows remote attackers to cause a denial of service (assertion failure and daemon restart) via a zero DH g^x value in a KE payload in a IKE packet.
https://security.gentoo.org/glsa/201603-13
https://lists.openswan.org/pipermail/users/2015-August/023401.html
https://libreswan.org/security/CVE-2015-3240/CVE-2015-3240.txt
http://www.securitytracker.com/id/1033418
http://www.securityfocus.com/bid/77536
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html