libreswan 3.9 through 3.12 allows remote attackers to cause a denial of service (daemon restart) via an IKEv1 packet with (1) unassigned bits set in the IPSEC DOI value or (2) the next payload value set to ISAKMP_NEXT_SAK.
https://security.gentoo.org/glsa/201603-13
https://libreswan.org/security/CVE-2015-3204/CVE-2015-3204.txt