racoon before 20040407b allows remote attackers to cause a denial of service (infinite loop and dropped connections) via an IKE message with a malformed Generic Payload Header containing invalid (1) "Security Association Next Payload" and (2) "RESERVED" fields.
https://exchange.xforce.ibmcloud.com/vulnerabilities/15893
http://www.vuxml.org/freebsd/40fcf20f-8891-11d8-90d1-0020ed76ef5a.html