ubuntu-cve-2020-12667
Vulnerability from osv_ubuntu
Published
2020-05-19 13:15
Modified
2026-04-22 07:39
Summary
Details

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.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "knot-resolver",
            "binary_version": "1.0.0~beta3-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "knot-resolver",
        "purl": "pkg:deb/ubuntu/knot-resolver@1.0.0~beta3-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0.0~beta2-123-g6134920-1",
        "1.0.0~beta3-1",
        "1.0.0~beta3-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "knot-resolver",
            "binary_version": "2.1.1-1ubuntu0.1~esm2"
          },
          {
            "binary_name": "knot-resolver-module-http",
            "binary_version": "2.1.1-1ubuntu0.1~esm2"
          },
          {
            "binary_name": "libkres6",
            "binary_version": "2.1.1-1ubuntu0.1~esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "knot-resolver",
        "purl": "pkg:deb/ubuntu/knot-resolver@2.1.1-1ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.3.3-1",
        "1.5.0-4",
        "1.5.1-1",
        "1.5.2-1",
        "2.0.0-3",
        "2.1.0-1",
        "2.1.0-2",
        "2.1.1-1",
        "2.1.1-1ubuntu0.1~esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "knot-resolver",
            "binary_version": "3.2.1-3ubuntu2.2"
          },
          {
            "binary_name": "knot-resolver-module-http",
            "binary_version": "3.2.1-3ubuntu2.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "knot-resolver",
        "purl": "pkg:deb/ubuntu/knot-resolver@3.2.1-3ubuntu2.2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.2.1-3ubuntu2.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.2.1-3",
        "3.2.1-3ubuntu1",
        "3.2.1-3ubuntu2",
        "3.2.1-3ubuntu2.1"
      ]
    }
  ],
  "aliases": [],
  "details": "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.",
  "id": "UBUNTU-CVE-2020-12667",
  "modified": "2026-04-22T07:39:24Z",
  "published": "2020-05-19T13:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2020-12667"
    },
    {
      "type": "REPORT",
      "url": "https://en.blog.nic.cz/2020/05/19/nxnsattack-upgrade-resolvers-to-stop-new-kind-of-random-subdomain-attack/"
    },
    {
      "type": "REPORT",
      "url": "http://cyber-security-group.cs.tau.ac.il/#"
    },
    {
      "type": "REPORT",
      "url": "http://www.openwall.com/lists/oss-security/2020/05/19/2"
    },
    {
      "type": "REPORT",
      "url": "https://www.knot-resolver.cz/2020-05-19-knot-resolver-5.1.1.html"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2020-12667"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-7047-1"
    }
  ],
  "related": [
    "USN-7047-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2020-12667"
  ]
}



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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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