CVE-2026-52863

{
  "id": "CVE-2026-52863",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-22T14:17:20.757",
  "lastModified": "2026-10-24T13:10:00.147",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In NLnet Labs Unbound 1.25.0 up to and including 1.25.1, a fix that makes the 'respip' and 'dns64' modules work together, creates a shallow copy of the view name in effect that could lead to memory corruption if the owner of the original view name is jostled out when Unbound is under pressure. Unbound needs to be configured with one of 'respip'/'rpz' modules, together with a module that can attach subqueries (respip CNAME redirection, dns64, subnetcache) and a configured 'access-control-view' while Unbound is under pressure so that joslte logic kicks in and starts dropping slow queries. The subquery is getting a shallow copy of the view name and if the super query which owns the view name is jostled out, memory corruption can occur. Likelihood of a crash is low, since it relies heavily on the underlying memory allocator and the memory layout. Debug memory builds (e.g., ASAN) that catch the free terminate the server."
    },
    {
      "lang": "es",
      "value": "En NLnet Labs Unbound 1.25.0 hasta la versión 1.25.1 inclusive, una corrección que hace que los módulos ’respip’ y ’dns64’ funcionen juntos, crea una copia superficial del nombre de vista en efecto que podría conducir a corrupción de memoria si el propietario del nombre de vista original es desalojado cuando Unbound está bajo presión. Unbound necesita ser configurado con uno de los módulos ’respip’/’rpz’, junto con un módulo que pueda adjuntar subconsultas (redirección CNAME de respip, dns64, subnetcache) y una ’access-control-view’ configurada mientras Unbound está bajo presión para que la lógica de desalojo se active y comience a descartar consultas lentas. La subconsulta está obteniendo una copia superficial del nombre de vista y si la superconsulta que posee el nombre de vista es desalojada, puede ocurrir corrupción de memoria. La probabilidad de un fallo es baja, ya que depende en gran medida del asignador de memoria subyacente y del diseño de la memoria. Las compilaciones de memoria de depuración (p. ej., ASAN) que detectan la liberación terminan el servidor."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "NLnet Labs",
          "product": "Unbound",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "1.25.0",
              "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:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-22T14:17:14.001060Z",
          "id": "CVE-2026-52863",
          "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-416"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "1.25.0",
              "versionEndExcluding": "1.25.2",
              "matchCriteriaId": "2E96BD04-27A3-4B2F-AB37-A5887AED393A"
            }
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  ],
  "references": [
    {
      "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-52863.txt",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ]
}