CVE-2026-12244 Heap overflow and crash with crafted SVCB RR

If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a DNS message with a special crafted SVCB RR with an rdata size of 65512, that let's an uint16t variable that is used to allocate space needed for the RR wrap because total size 65535,...