This code is handling the option field in incoming IPv6 packets. The object being manipulated is a linked list of packet structs. And that linked list is almost always a single member list.

IP breaks down data into smaller packets, so that it can transmit over a network smoothly. There are currently two versions of Internet Protocol: IPv4 (IP version 4) and IPv6 (IP version 6).

It is described as a Windows TCP/IP RCE flaw, in which an unauthenticated user could spam specially crafted IPv6 packets ...

Perhaps ironically, this might as [Geoff] postulates be a consequence of a lack of planning and pushing of IPv6 in the 1990s, with the rise of mobile devices and their use of non-packet-based 3G ...