CVE-2020-12244Network attack vector

DNSSEC bypass via unvalidated NXDOMAIN answer records

Published May 19, 2020 · Updated Aug 4, 2024

DNSSEC validation bypass in PowerDNS Recursor 4.1.0 through 4.3.0 allows man-in-the-middle attackers to spoof denial of existence. SyncRes::processAnswer accepts answer-section records from an NXDOMAIN response lacking an SOA without properly validating their DNSSEC signatures. The attacker must control the DNS response path and can make an existing name appear nonexistent, without reported system compromise.

CVSS severity7.5
High
EPSS probability2.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DNSSEC validation bypass in PowerDNS Recursor 4.1.0 through 4.3.0 allows man-in-the-middle attackers to spoof denial of existence. SyncRes::processAnswer accepts answer-section records from an NXDOMAIN response lacking an SOA without properly validating their DNSSEC signatures. The attacker must control the DNS response path and can make an existing name appear nonexistent, without reported system compromise.

The record

CVE
CVE-2020-12244
Published
May 19, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-347, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 19, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

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-347Improper Verification of Cryptographic Signature
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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