CVE-2022-0635Network attack vector

Remote DNS service termination via DNAME query sequence

Published Mar 23, 2022 · Updated Sep 17, 2024

Reachable assertion in BIND 9 9.18.0 allows remote attackers to interrupt DNS service via crafted query sequences. The query_dname function asserts while processing repeated DNAME lookups when synth-from-dnssec is enabled, causing named to terminate. The condition requires a DNSSEC-validating resolver with the default synth-from-dnssec behavior; the bounded impact is loss of DNS service until the daemon restarts.

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

Reachable assertion in BIND 9 9.18.0 allows remote attackers to interrupt DNS service via crafted query sequences. The query_dname function asserts while processing repeated DNAME lookups when synth-from-dnssec is enabled, causing named to terminate. The condition requires a DNSSEC-validating resolver with the default synth-from-dnssec behavior; the bounded impact is loss of DNS service until the daemon restarts.

The record

CVE
CVE-2022-0635
Published
Mar 23, 2022
Updated
Sep 17, 2024
Vendor
Internet Systems Consortium
Product
BIND 9
Classifications
CWE-617, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record 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=Open Source Branch 9.18 9.18.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Internet Systems Consortium · BIND 9version=Open Source Branch 9.18 9.18.0

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.0Internet Systems ConsortiumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C
7.5Internet Systems Consortium (via NVD)CVSS: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-617Reachable Assertion
T1499.002Service Exhaustion

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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