Here’s a nasty problem: Windows 7 has an IPv6 flaw

Oh yes, this is just what we need. Everyone is jumping on the Windows 7 bandwagon, just in time for researchers to find a fatal flaw in the Windows 7 IPv6 stack. Basically it can inflict a slow death on your workstation, as system functions fail in sequence until lockup. The vulnerability lies in the implementation of DHCPv6. And like many flaws, it can be exploited from other platforms, for instance a mis-configured Linux DHCP server.

See the ZDnet article at: http://www.zdnet.co.uk/news/security-threats/2011/08/17/ipv6-handling-flaw-found-in-windows-7-40093710/ . (And thanks to DW!)