CVE-2026-123593 and is rated Medium severity with a CVSS score of 4.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
What to do next
Remediation and response
Microsoft Security Response Center guidance
Vendor revision: Nov 11, 2026
Release Notes
CISA KEVNot listedBased on the latest collected catalog
EPSS0.2%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-123593?
Hickory DNS hickory-net 0.26.0-beta.1 before 0.26.2 and hickory-proto 0.24.0 through 0.26.0-alpha.1 compare DNSKEY public keys against DNSSEC trust anchors without checking the DNSKEY record name, so an RRset made up only of trusted keys is accepted without RRSIG verification.
Attackers able to spoof or control name server responses can replace a secure zone's DNSKEY RRset with the root zone's keys, and use a large TTL to keep it cached.