CVE-2026-44690

{
  "id": "CVE-2026-44690",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-22T14:17:19.153",
  "lastModified": "2026-10-24T13:10:00.147",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, insufficient validation of the RRSIG.Labels field combined with premature cache writes during RFC 8198 aggressive NSEC processing leads to cache poisoning that permits a malicious actor controlling a single delegated zone to poison arbitrary sibling zones under NSEC-signed parent domains. A malicious actor with one registered domain under an NSEC-signed TLD can serve malicious insecure DNS responses for unrelated sibling domains (sharing the same parent zone). Arbitrary delegations that do not exist under the parent domain and are covered by the parent's NSEC chain can be brought into insecure existence by fraudulent wildcard DS records (less labels than expected, unknown algorithm) from the malicious sibling domain. This allows the malicious actor to inject insecure wildcard records for those delegations."
    },
    {
      "lang": "es",
      "value": "En NLnet Labs Unbound 1.7.0 hasta la versión 1.25.1 inclusive, la validación insuficiente del campo RRSIG.Labels combinada con escrituras prematuras en la caché durante el procesamiento agresivo de NSEC de RFC 8198 conduce a un envenenamiento de caché que permite a un actor malicioso que controla una única zona delegada envenenar zonas hermanas arbitrarias bajo dominios padre firmados con NSEC. Un actor malicioso con un dominio registrado bajo un TLD firmado con NSEC puede servir respuestas DNS maliciosas e inseguras para dominios hermanos no relacionados (que comparten la misma zona padre). Delegaciones arbitrarias que no existen bajo el dominio padre y están cubiertas por la cadena NSEC del padre pueden ser traídas a una existencia insegura mediante registros DS comodín fraudulentos (menos etiquetas de las esperadas, algoritmo desconocido) del dominio hermano malicioso. Esto permite al actor malicioso inyectar registros comodín inseguros para esas delegaciones."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "NLnet Labs",
          "product": "Unbound",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "1.7.0",
              "lessThan": "1.25.2",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-22T18:56:03.722157Z",
          "id": "CVE-2026-44690",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-345"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "1.7.0",
              "versionEndExcluding": "1.25.2",
              "matchCriteriaId": "E2331CF5-0B7D-4505-A5A0-408593040279"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-44690.txt",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ]
}