Openswan 2.6.39 and earlier allows remote attackers to cause a denial of service (NULL pointer dereference and IKE daemon restart) via IKEv2 packets that lack expected payloads.
https://libreswan.org/security/CVE-2013-6467/CVE-2013-6467.txt
https://exchange.xforce.ibmcloud.com/vulnerabilities/90524
https://cert.vde.com/en-us/advisories/vde-2017-001
http://www.securityfocus.com/bid/65155