IPv6 is the latest Internet protocol which aims to solve the address quantity shortfall inherent to IPv4. And while there are no security risks directly associated with the new protocol there are a few things to understand before utilizing this new technology.
Most system administrators are familiar with IPv4 and the work-arounds that were put in place to make IPv4 work. One of these work-arounds is network address translation, or NAT. NAT is traditionally used to keep the number of needed public IP addresses to a minimum when setting up a local area network. Systems on these networks do not all require public IP addresses and valuable address space can be saved by implementing this technology. There are some security features that were side effects to NAT; the biggest being that outside traffic cannot make it inside the network unless a port is forwarded across the router. Because IPv6 solves the addressing problem there is no longer a need to use NAT. Everything can have a public IP address and, by extension, everything is not publically routable across the Internet when physical and logical connections are made.
Another thing to worry about is how security software deals with this new protocol. iptables does not know or understand IPv6 and so it ignores those packets altogether. That means if your network is utilizing IPv6 and you have not activated ip6tables then you have just left the door to your system open to the world.
Using IPv6 is not dangerous as long as you know and understand the changes that your system's software went through to make it possible to use this new network protocol.