Zonemaster-LDNS crashes when the response has a SVCB record in the additional section

[matsduf]

I tested the zone p.axfr.net. The name server includes an SVCB record in additional section when the NS record is listed in the authority section, e.g.

; <<>> DiG 9.20.15 <<>> @77.72.230.63 p.axfr.net soa +mult
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 36405
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 3
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;p.axfr.net.		IN SOA

;; ANSWER SECTION:
p.axfr.net.		7200 IN	SOA when.pigs.can.fly. hostmaster.johani.org. (
				2023122633 ; serial
				7200       ; refresh (2 hours)
				1800       ; retry (30 minutes)
				604800     ; expire (1 week)
				7200       ; minimum (2 hours)
				)

;; AUTHORITY SECTION:
p.axfr.net.		300 IN NS ns1.p.axfr.net.

;; ADDITIONAL SECTION:
ns1.p.axfr.net.		300 IN A 77.72.230.63
ns1.p.axfr.net.		300 IN AAAA 2a01:3f0:1:2::63
_dns.ns1.p.axfr.net.	10800 IN SVCB 1 . alpn="doq,dot,doh,do53" ipv4hint=77.72.230.63 ipv6hint=2a01:3f0:1:2::63 key65280="doq:100,dot:50,do53:0" key65281="3 1 1 27593C5D05727654041BC1C2E24EC41DAF48E1C467E58DE328A3D7CDFD4CEB4A"

;; Query time: 5 msec
;; SERVER: 77.72.230.63#53(77.72.230.63) (UDP)
;; WHEN: Sat Dec 20 16:36:22 UTC 2025
;; MSG SIZE  rcvd: 404

Zonemaster-LDNS crashes when Zonemaster tries to test zone p.axfr.net. What assumptions does Zonemaster do about the content of the additional section?

$ zonemaster-cli --show-testcase --test basic p.axfr.net --level info

Seconds Level    Testcase       Message
======= ======== ============== =======
   0.00 INFO     Unspecified    Using version v8.1.0 of the Zonemaster engine.
  26.77 INFO     Basic01        The parent zone is "axfr.net" as returned from name servers "nsa.axfr.net/2a01:3f0:1:2:1::4033;nsa.axfr.net/77.72.231.134;nsb.axfr.net/2a01:3f0:1:2::61;nsb.axfr.net/77.72.230.61;nsc.axfr.net/41.76.135.53".
  26.77 INFO     Basic01        The zone "p.axfr.net" is found.
  26.81 CRITICAL Unspecified    Fatal error in Zonemaster::Engine::Test::Basic: Can't locate object method "check_rd_count" via package "Zonemaster::LDNS::RR::SVCB" at /usr/local/lib/perl5/site_perl/mach/5.42/Zonemaster/LDNS/Packet.pm line 89.

  26.81 CRITICAL Unspecified    Not enough data about p.axfr.net was found to be able to run tests.

The cache from the zonemaster-cli command has been saved into p.axfr.net.save.zip