CVE-2026-5947

Estado: ModificadaMedia (5.9)—
Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature. If, during that validation, the "recursive-clients" limit is reached (as would occur during a query flood), and that same DNS message is discarded per the limit, there is a brief window of time while the SIG(0) validation may attempt to read the now-discarded DNS message. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.28 through 9.18.49 and 9.18.28-S1 through 9.18.49-S1 are NOT affected.
CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 5.9
Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.80%
Percentil entre todas las CVEs puntuadas: 55
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).
Tecnologías afectadas (1)

ISC — Bind
CWE

CWE-362, CWE-416
CWE-367
Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-5947",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-5947",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-05-20T13:39:15.454199Z"
        }
      }
    ],
    "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
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.9,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 2.2
      },
      {
        "type": "Secondary",
        "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
        "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": "9.20.22"
            },
            {
              "status": "affected",
              "version": "9.21.0",
              "versionType": "custom",
              "lessThanOrEqual": "9.21.21"
            },
            {
              "status": "affected",
              "version": "9.20.9-S1",
              "versionType": "custom",
              "lessThanOrEqual": "9.20.22-S1"
            },
            {
              "status": "unaffected",
              "version": "9.18.28",
              "versionType": "custom",
              "lessThanOrEqual": "9.18.49"
            },
            {
              "status": "unaffected",
              "version": "9.18.28-S1",
              "versionType": "custom",
              "lessThanOrEqual": "9.18.49-S1"
            }
          ],
          "defaultStatus": "unaffected"
        }
      ]
    },
    {
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
      "affectedData": [
        {
          "cpes": [
            "cpe:/a:redhat:hummingbird:1"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Hardened Images",
          "versions": [
            {
              "status": "unaffected",
              "version": "9.18.48-1.1.hum1",
              "lessThan": "*",
              "versionType": "rpm"
            }
          ],
          "packageName": "bind-main",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "affected"
        },
        {
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:10"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 10",
          "packageName": "bind",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:6"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 6",
          "packageName": "bind",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:7"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 7",
          "packageName": "bind",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:8"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 8",
          "packageName": "bind",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:8"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 8",
          "packageName": "bind9.16",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:9"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 9",
          "packageName": "bind",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:9"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 9",
          "packageName": "bind9.18",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:9"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 9",
          "packageName": "dhcp",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:openshift:4"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat OpenShift Container Platform 4",
          "packageName": "openshift/ose-rhel-coreos-9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-05-20T13:16:40.303",
  "references": [
    {
      "url": "https://downloads.isc.org/isc/bind9/9.20.23",
      "tags": [
        "Patch"
      ],
      "source": "security-officer@isc.org"
    },
    {
      "url": "https://downloads.isc.org/isc/bind9/9.21.22",
      "tags": [
        "Patch"
      ],
      "source": "security-officer@isc.org"
    },
    {
      "url": "https://kb.isc.org/docs/cve-2026-5947",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security-officer@isc.org"
    },
    {
      "url": "https://access.redhat.com/errata/RHSA-2026:7412",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    },
    {
      "url": "https://access.redhat.com/security/cve/CVE-2026-5947",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    },
    {
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2479772",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    },
    {
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5947.json",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-officer@isc.org",
      "description": [
        {
          "lang": "en",
          "value": "CWE-362"
        },
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    },
    {
      "type": "Secondary",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
      "description": [
        {
          "lang": "en",
          "value": "CWE-367"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Undefined behavior may result due to a race condition leading to a use-after-free violation.  If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature.  If, during that validation, the \"recursive-clients\" limit is reached (as would occur during a query flood), and that same DNS message is discarded per the limit, there is a brief window of time while the SIG(0) validation may attempt to read the now-discarded DNS message.\nThis issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1.\nBIND 9 versions 9.18.28 through 9.18.49 and 9.18.28-S1 through 9.18.49-S1 are NOT affected."
    },
    {
      "lang": "es",
      "value": "El comportamiento indefinido puede resultar debido a una condición de carrera que lleva a una violación de uso después de liberación. Si BIND recibe un mensaje DNS entrante firmado con SIG(0), comienza a trabajar para validar esa firma. Si, durante esa validación, se alcanza el límite de 'recursive-clients' (como ocurriría durante una inundación de consultas), y ese mismo mensaje DNS es descartado según el límite, hay una breve ventana de tiempo mientras la validación de SIG(0) puede intentar leer el mensaje DNS ahora descartado.\nEste problema afecta a las versiones de BIND 9 9.20.0 a 9.20.22, 9.21.0 a 9.21.21, y 9.20.9-S1 a 9.20.22-S1.\nLas versiones de BIND 9 9.18.28 a 9.18.49 y 9.18.28-S1 a 9.18.49-S1 NO están afectadas."
    }
  ],
  "lastModified": "2026-08-24T13:19:13.360",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "D92461F1-BA01-479E-B740-38855CC216E6",
              "versionEndExcluding": "9.20.23",
              "versionStartIncluding": "9.20.0"
            },
            {
              "criteria": "cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "B254E8E7-3F57-4552-ACBF-623FA481B697",
              "versionEndExcluding": "9.21.22",
              "versionStartIncluding": "9.21.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security-officer@isc.org"
}