IKEv2 misconfiguration can cause libreswan to abort and restart

The Libreswan Project was notified of an issue causing libreswan to restart under some IKEv2 retransmit scenarios when a connection is configured to use PreSharedKeys (authby=secret) and the connection cannot find a matching configured secret. When such a connection is automatically added on startup using the auto= keyword, it can cause repeated crashes leading to a Denial of Service.