Description
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.
Published: 2026-10-21
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
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Remediation

Vendor Solution

This issue is fixed starting with version 1.26.2

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History

Wed, 21 Oct 2026 09:15:00 +0000

Type Values Removed Values Added
Description 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.
Title DNS-over-QUIC (DoQ) path-migration can lead to use-after-free on multi-threaded deployments.
Weaknesses CWE-416
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: NLnet Labs

Published:

Updated: 2026-10-21T08:57:41.106Z

Reserved: 2026-10-14T09:16:14.090Z

Link: CVE-2026-97206

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-21T09:17:08.473

Modified: 2026-10-21T09:17:08.473

Link: CVE-2026-97206

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-21T16:30:06Z

Weaknesses