Assertion in libngtcp2 when under pressure in high concurrency DNS-over-QUIC environments

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-14586
StatePUBLISHED
AssignerNLnet Labs
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-22 14:17:15 UTC
Updated2026-07-22 20:33:11 UTC
DescriptionIn NLnet Labs Unbound 1.22.0 up to and including 1.25.1, in DNS-over-QUIC environments, with high concurrency and under pressure, an assertion in libngtcp2 about monotonic timestamps could trigger and result in server termination and thus denial of service. When interfacing with libngtcp2, for DNS-over-QUIC support in Unbound, it is expected to use monotonic time. Unbound was using realtime instead, and in DoQ environments with high concurrency and under pressure, an assert in libngtcp2 for the quic timestamp would trigger and terminate the server.This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces.

Risk And Classification

Primary CVSS: v3.1 5.9 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-617 | CWE-617 CWE-617: Reachable Assertion

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNACVSS5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA NLnet Labs Unbound affected 1.22.0 1.25.2 semver Not specified

References

ReferenceSourceLinkTags
www.nlnetlabs.nl/downloads/unbound/CVE-2026-14586.txt [email protected] www.nlnetlabs.nl
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Kunta Chu (Tsinghua University) (en)

CNA: Kaihua Wang (Tsinghua University) (en)

CNA: Jianjun Chen (Tsinghua University) (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-05-08T00:00:00.000ZIssue reported by Kunta Chu
CNA2026-07-02T00:00:00.000ZNLnet Labs shares patch with Kunta Chu
CNA2026-07-03T00:00:00.000ZKunta Chu verifies patch
CNA2026-07-22T00:00:00.000ZFixes released with version 1.25.2

Solutions

CNA: This issue is fixed starting with version 1.25.2

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