CVE-2026-14586Network attack vector

Remote service crash via nonmonotonic QUIC timestamps

Published Jul 22, 2026 · Updated Jul 22, 2026

Reachable assertion in NLnet Labs Unbound 1.22.0 through 1.25.1 allows remote attackers to terminate the server via DNS-over-QUIC traffic. The DoQ integration supplies realtime timestamps where libngtcp2 requires monotonic time, so high concurrency and resource pressure can violate its QUIC timestamp assertion. Exposure requires a build compiled with --with-libngtcp2 and a quic-port configured on a listening interface; successful triggering crashes the resolver and interrupts DNS service.

CVSS severity5.9
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in NLnet Labs Unbound 1.22.0 through 1.25.1 allows remote attackers to terminate the server via DNS-over-QUIC traffic. The DoQ integration supplies realtime timestamps where libngtcp2 requires monotonic time, so high concurrency and resource pressure can violate its QUIC timestamp assertion. Exposure requires a build compiled with --with-libngtcp2 and a quic-port configured on a listening interface; successful triggering crashes the resolver and interrupts DNS service.

The record

CVE
CVE-2026-14586
Published
Jul 22, 2026
Updated
Jul 22, 2026
Vendor
NLnet Labs
Product
Unbound
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.22.0 <1.25.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NLnet Labs · Unboundversion=1.22.0 <1.25.2

Published CVSS scores

5.9NLnet LabsCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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