CVE-2026-3238: source4 WINS server NULL pointer dereference in
nbtd_winsserver_register/query/release(); craft NBT packets with
qdcount=0, arcount=0, or empty netbios addresses crash the nbt process
on servers running wins support = yes (typical AD DC role). Fix
dissolves direct variable initialization and adds NBTD_ASSERT_PACKET
qdcount/arcount/length validation before any packet array dereference.