CVE-2022-3204Network attack vector

Service degradation via nonresponsive malicious delegations

Published Sep 26, 2022 · Updated May 5, 2025

Resource exhaustion in NLnet Labs Unbound 1.16.2 and earlier allows remote attackers to degrade DNS service via crafted queries. The resolver follows a malicious delegation containing many nonresponsive nameservers, repeatedly attempting resolution and missing-record cache lookups until hard limits are reached. The attacker must control the delegated DNS data and induce queries for dependent records; orchestrated requests consume resolver time and resources, degrading or denying DNS responses.

CVSS severity7.5
High
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in NLnet Labs Unbound 1.16.2 and earlier allows remote attackers to degrade DNS service via crafted queries. The resolver follows a malicious delegation containing many nonresponsive nameservers, repeatedly attempting resolution and missing-record cache lookups until hard limits are reached. The attacker must control the delegated DNS data and induce queries for dependent records; orchestrated requests consume resolver time and resources, degrading or denying DNS responses.

The record

CVE
CVE-2022-3204
Published
Sep 26, 2022
Updated
May 5, 2025
Vendor
NLnet Labs
Product
Unbound
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 26, 2022CVE publishedPublication date reported by the CVE source.
  2. May 5, 2025Record 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=unspecified <=1.16.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NLnet Labs · Unboundversion=unspecified <=1.16.2

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/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-400Uncontrolled Resource Consumption
T1499.004Endpoint Denial of Service: Application 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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