CVE-2026-7656: Authentication Bypass by Spoofing

The IPv6 Neighbor Discovery handlers in subsys/net/ip/ipv6nbr.c handlerainput, handlensinput, handlenainput used an incorrect boolean expression that combined the RFC 4861 validity checks with the ICMPv6 code check using the wrong operator precedence: the form was length/hop/source/target checks ...