The remote host is missing an update to the system as announced in the referenced advisory FreeBSD-SA-07:03.ipv6.asc

Upgrade your system to the appropriate stable release or security branch dated after the correction date https://secure1.securityspace.com/smysecure/catid.html?in=FreeBSD-SA-07:03.ipv6.asc

IPv6 provides a routing header option which allows a packet sender to indicate how the packet should be routed, overriding the routing knowledge present in a network. This functionality is roughly equivalent to the source routing option in IPv4. All nodes in an IPv6 network -- both routers and hosts -- are required by RFC 2640 to process such headers. There is no mechanism for preventing IPv6 routing headers from being used to route packets over the same link(s) many times.