Security advisory

{
  "id": "4f9fae4811a8896b9306f99359e8ef31eef23d3b46f3998e47427a6cbf50a3f1",
  "url": "https://osv.dev/vulnerability/CVE-2021-40083",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-40083",
    "summary": "Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).",
    "evidence": "osv:CVE-2021-40083",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-40083",
      "aliases": [
        "CVE-2021-40083"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/cz-nic/knot-resolver",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "ae3c81600a6ce5909bd3abc9dbc4d31e89ef3179"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:nic:knot_resolver:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "5.3.2"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v5.3.1",
            "v5.3.0",
            "v5.2.1",
            "v5.2.0",
            "v5.1.3",
            "v5.1.2",
            "v5.1.1",
            "v5.1.0",
            "v5.0.1",
            "v5.0.0",
            "v4.3.0",
            "v4.2.2",
            "v4.2.0",
            "v4.1.0",
            "v4.0.0",
            "v3.2.1",
            "v3.2.0",
            "v3.1.0",
            "v3.0.0",
            "v2.4.0",
            "v2.3.0",
            "v2.2.0",
            "v2.1.1",
            "v2.1.0",
            "v2.0.0",
            "v1.5.1",
            "v1.5.0",
            "v1.4.0",
            "v1.3.3",
            "v1.3.2",
            "v1.3.1",
            "v1.3.0",
            "v1.2.6",
            "v1.2.1",
            "v1.2.0",
            "v1.2.0-rc3",
            "v1.2.0-rc2",
            "v1.2.0-rc1",
            "v1.1.1",
            "v1.1.0",
            "v1.0.0",
            "v1.0.0-beta3",
            "v1.0.0-beta2",
            "v1.0.0-beta1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-40083.json"
          }
        }
      ],
      "modified": "2026-10-24T10:30:39.954919840Z",
      "provider": "osv",
      "references": [
        "https://gitlab.nic.cz/knot/knot-resolver/-/merge_requests/1169"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-40083",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 434795,
  "published_at": "2021-08-25T01:15:11.087+00:00"
}