Published Oct 21, 2026Sources checked Oct 23, 2026
7.5HIGHCVSS out of 10
What this means
Review the available evidence
CVE-2026-97206 and is rated High severity with a CVSS score of 7.5. 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: Oct 23, 2026
Release Notes
CISA KEVNot listedBased on the latest collected catalog
EPSS0.3%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-97206?
NLnet Labs Unbound, 1.22.0 up to and including version 1.26.1, contains a DNS-over-QUIC (DoQ) lifetime bug reachable by a remote DoQ client under multi-threaded operation. A client-triggered QUIC path migration can enter stream/connection cleanup while a mesh reply still retains a pointer to the DoQ stream.
Cleanup frees the DoQ stream and when the pending mesh reply later completes it dereferences a stale pointer leading to a crash.