Vulnerability Report

CVE-2020-12667

Title: Knot Resolver NXNSAttack Traffic Amplification

DoS

Proof Of Concept

No public PoC currently indexed for CVE-2020-12667.

CWE Category CWE-400
Published Date May 19, 2020
Modified Date Jun 17, 2026
Exploit Status Not Found
Score 7.5 CVSS v3.1
Exploit Probability (EPSS)
2.62%

Vulnerability Summary

CVE-2020-12667: Knot Resolver before 5.1.1 allows traffic amplification via a crafted DNS answer from an attacker-controlled server, aka an "NXNSAttack" issue. This is triggered by random subdomains in the NSDNAME in NS records.

Impacted Vendors

N
nic 1

Reference Links

http://cyber-security-group.cs.tau.ac.il/# http://www.openwall.com/lists/oss-security/2020/05/19/2 https://en.blog.nic.cz/2020/05/19/nxnsattack-upgrade-resolvers-to-stop-new-kind-of-random-subdomain-attack/ https://lists.debian.org/debian-lts-announce/2024/04/msg00017.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/76Y4FITMOH6RVPWAANGV7NB2ZHPJJGDQ/ https://www.knot-resolver.cz/2020-05-19-knot-resolver-5.1.1.html http://cyber-security-group.cs.tau.ac.il/# http://www.openwall.com/lists/oss-security/2020/05/19/2 https://en.blog.nic.cz/2020/05/19/nxnsattack-upgrade-resolvers-to-stop-new-kind-of-random-subdomain-attack/ https://lists.debian.org/debian-lts-announce/2024/04/msg00017.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/76Y4FITMOH6RVPWAANGV7NB2ZHPJJGDQ/ https://www.knot-resolver.cz/2020-05-19-knot-resolver-5.1.1.html
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v3.1
Source Entity 134c704f-9b21-4f2e-91b3-4a467353bcc0
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v2.0
Source Entity [email protected]
Severity MEDIUM
5.0
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:L/Au:N/C:N/I:N/A:P

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2020-12667 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Stack

No specific products linked.