CVE-2020-12667
HIGHCVSS 7.5/10EPSS 2.62%
Last modified
CVE-2020-12667 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 2.62% chance of exploitation in the next 30 days.
Description
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Nic | Knot Resolver | < 5.1.1 |
References
- http://cyber-security-group.cs.tau.ac.il/#Technical Description, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2020/05/19/2Mailing List, Third Party Advisory
- https://en.blog.nic.cz/2020/05/19/nxnsattack-upgrade-resolvers-to-stop-new-kind-of-random-subdomain-attack/Technical Description, Vendor Advisory
- https://www.knot-resolver.cz/2020-05-19-knot-resolver-5.1.1.htmlRelease Notes, Vendor Advisory
- http://cyber-security-group.cs.tau.ac.il/#Technical Description, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2020/05/19/2Mailing List, Third Party Advisory
- https://en.blog.nic.cz/2020/05/19/nxnsattack-upgrade-resolvers-to-stop-new-kind-of-random-subdomain-attack/Technical Description, Vendor Advisory
- https://www.knot-resolver.cz/2020-05-19-knot-resolver-5.1.1.htmlRelease Notes, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is 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.
How severe is CVE-2020-12667?
CVE-2020-12667 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.62% probability of exploitation in the next 30 days.
How do I fix CVE-2020-12667?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2020-12667?
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Scan your code nowSource: NVD / NIST