The IKE implementation in Clavister CorePlus before 8.80.03, and 8.80.00, does not properly validate certificates during IKE negotiation, which allows remote attackers to cause a denial of service (gateway stop) via certain certificates.
https://exchange.xforce.ibmcloud.com/vulnerabilities/35370
http://www.clavister.com/releasenotes/CorePlus_Release_Notes_8_81_01.pdf
http://www.clavister.com/releasenotes/CorePlus_Release_Notes_8_80_04.pdf