Problem Description:
The Neighbor Discover Protocol allows a local router to
advertise a suggested Current Hop Limit value of a link,
which will replace Current Hop Limit on an interface connected
to the link on the FreeBSD system.
Impact:
When the Current Hop Limit (similar to IPv4's TTL) is
small, IPv6 packets may get dropped before they reached
their destinations.
By sending specifically crafted Router Advertisement
packets, an attacker on the local network can cause the
FreeBSD system to lose the ability to communicate with
another IPv6 node on a different network.