Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records.
1:9.16.48-0ubuntu0.20.04.11:9.11.16+dfsg-3~build11:9.11.16+dfsg-3~ubuntu12.90-0ubuntu0.20.04.13.2.1-33.2.1-3ubuntu13.2.1-3ubuntu23.2.1-3ubuntu2.13.2.1-3ubuntu2.21.9.4-2ubuntu1.51:9.18.18-0ubuntu0.22.04.22.90-0ubuntu0.22.04.11.13.1-1ubuntu5.41.19.1-1ubuntu14.4.3-P1-4ubuntu2Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:NI:NA:HCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H