CVE-2026-40209

{
  "id": "CVE-2026-40209",
  "sourceIdentifier": "[email protected]",
  "published": "2026-06-25T13:16:39.527",
  "lastModified": "2026-10-25T23:10:00.167",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors."
    },
    {
      "lang": "es",
      "value": "Un atacante podría ser capaz de causar que las conexiones TCP salientes al backend se queden atascadas hasta que se agote el tiempo de espera en lugar de ser liberadas inmediatamente, enviando consultas IXFR. Esto podría usarse para causar una denegación de servicio si hay un límite en el número de conexiones concurrentes a este backend, o si el proceso se queda sin descriptores de archivo."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "PowerDNS",
          "product": "DNSdist",
          "defaultStatus": "unaffected",
          "collectionURL": "https://repo.powerdns.com/",
          "packageName": "dnsdist",
          "modules": [
            "DNS over TCP to the backend"
          ],
          "programFiles": [
            "dnsdist-tcp-downstream.cc"
          ],
          "repo": "https://github.com/PowerDNS/pdns",
          "versions": [
            {
              "version": "1.9.0",
              "lessThan": "1.9.15",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "2.0.0",
              "lessThan": "2.0.7",
              "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:N/A:L",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "LOW"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-06-25T13:56:17.791790Z",
          "id": "CVE-2026-40209",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-772"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html",
      "source": "[email protected]"
    }
  ]
}