CVE-2025-40777

Estado: AplazadaAlta (7.5)—

If a `named` caching resolver is configured with `serve-stale-enable` `yes`, and with `stale-answer-client-timeout` set to `0` (the only allowable value other than `disabled`), and if the resolver, in the process of resolving a query, encounters a CNAME chain involving a specific combination of cached or authoritative records, the daemon will abort with an assertion failure. This issue affects BIND 9 versions 9.20.0 through 9.20.10, 9.21.0 through 9.21.9, and 9.20.9-S1 through 9.20.10-S1.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.98%
Percentil entre todas las CVEs puntuadas: 61
Fecha de la puntuación: 6/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access60 %
Impacto principalT1499 Endpoint Denial of Serviceimpact55 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

ISC — Bind^AI

CWE

CWE-617

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2025-40777",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-40777",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2025-07-18T14:25:41.033326Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-officer@isc.org",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security-officer@isc.org",
      "affectedData": [
        {
          "vendor": "ISC",
          "product": "BIND 9",
          "versions": [
            {
              "status": "affected",
              "version": "9.20.0",
              "versionType": "custom",
              "lessThanOrEqual": "9.20.10"
            },
            {
              "status": "affected",
              "version": "9.21.0",
              "versionType": "custom",
              "lessThanOrEqual": "9.21.9"
            },
            {
              "status": "affected",
              "version": "9.20.9-S1",
              "versionType": "custom",
              "lessThanOrEqual": "9.20.10-S1"
            },
            {
              "status": "unaffected",
              "version": "9.18.0",
              "versionType": "custom",
              "lessThanOrEqual": "9.18.37"
            },
            {
              "status": "unaffected",
              "version": "9.18.11-S1",
              "versionType": "custom",
              "lessThanOrEqual": "9.18.37-S1"
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          "defaultStatus": "unaffected"
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  "published": "2025-07-16T18:15:24.770",
  "references": [
    {
      "url": "https://kb.isc.org/docs/cve-2025-40777",
      "source": "security-officer@isc.org"
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2025/07/16/6",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-officer@isc.org",
      "description": [
        {
          "lang": "en",
          "value": "CWE-617"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "If a `named` caching resolver is configured with `serve-stale-enable` `yes`, and with `stale-answer-client-timeout` set to `0` (the only allowable value other than `disabled`), and if the resolver, in the process of resolving a query, encounters a CNAME chain involving a specific combination of cached or authoritative records, the daemon will abort with an assertion failure.\nThis issue affects BIND 9 versions 9.20.0 through 9.20.10, 9.21.0 through 9.21.9, and 9.20.9-S1 through 9.20.10-S1."
    },
    {
      "lang": "es",
      "value": "Si un solucionador de caché con nombre está configurado con `serve-stale-enable` `yes` y con `stale-answer-client-timeout` establecido en `0` (el único valor permitido aparte de `disabled`), y si el solucionador, al resolver una consulta, encuentra una cadena CNAME que involucra una combinación específica de registros en caché o autorizados, el daemon se interrumpirá con un error de aserción. Este problema afecta a las versiones de BIND 9 de la 9.20.0 a la 9.20.10, de la 9.21.0 a la 9.21.9 y de la 9.20.9-S1 a la 9.20.10-S1."
    }
  ],
  "lastModified": "2026-06-17T09:22:07.353",
  "sourceIdentifier": "security-officer@isc.org"
}