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CVE-2026-5950

Estado: AnalizadaMedia (5.3)—

An unbounded resend loop vulnerability exists in the BIND 9 resolver state machine during bad-server handling, enabling a remote unauthenticated attacker to cause severe resource exhaustion by sending queries that trigger specific retry conditions. This issue affects BIND 9 versions 9.18.36 through 9.18.48, 9.20.8 through 9.20.22, 9.21.7 through 9.21.21, 9.18.36-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.

CVSS

Probabilidad de explotación (EPSS)

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).

Tecnologías afectadas (1)

ISC — Bind

CWE

Referencias

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{
  "id": "CVE-2026-5950",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
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        "ssvcData": {
          "id": "CVE-2026-5950",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-05-20T13:38:40.421994Z"
        }
      }
    ],
    "cvssMetricV31": [
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          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "LOW",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 3.9
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  "affected": [
    {
      "source": "security-officer@isc.org",
      "affectedData": [
        {
          "vendor": "ISC",
          "product": "BIND 9",
          "versions": [
            {
              "status": "affected",
              "version": "9.18.36",
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  "published": "2026-05-20T13:16:40.450",
  "references": [
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      "url": "https://downloads.isc.org/isc/bind9/9.18.49",
      "tags": [
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    },
    {
      "url": "https://downloads.isc.org/isc/bind9/9.20.23",
      "tags": [
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      "url": "https://downloads.isc.org/isc/bind9/9.21.22",
      "tags": [
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      "url": "https://kb.isc.org/docs/cve-2026-5950",
      "tags": [
        "Vendor Advisory"
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      "source": "security-officer@isc.org"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-officer@isc.org",
      "description": [
        {
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          "value": "CWE-606"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "An unbounded resend loop vulnerability exists in the BIND 9 resolver state machine during bad-server handling, enabling a remote unauthenticated attacker to cause severe resource exhaustion by sending queries that trigger specific retry conditions.\nThis issue affects BIND 9 versions 9.18.36 through 9.18.48, 9.20.8 through 9.20.22, 9.21.7 through 9.21.21, 9.18.36-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de bucle de reenvío ilimitado existe en la máquina de estados del resolvedor de BIND 9 durante el manejo de servidores defectuosos, permitiendo a un atacante remoto no autenticado causar un agotamiento severo de recursos enviando consultas que activan condiciones de reintento específicas.\nEste problema afecta a las versiones de BIND 9 9.18.36 a 9.18.48, 9.20.8 a 9.20.22, 9.21.7 a 9.21.21, 9.18.36-S1 a 9.18.48-S1, y 9.20.9-S1 a 9.20.22-S1."
    }
  ],
  "lastModified": "2026-07-23T12:10:00.110",
  "configurations": [
    {
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