FKIE_CVE-2026-40209

Vulnerability from fkie_nvd - Published: 2026-06-25 13:16 - Updated: 2026-06-25 15:59
Severity
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Summary
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.
References
security@open-xchange.comhttps://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://repo.powerdns.com/",
          "defaultStatus": "unaffected",
          "modules": [
            "DNS over TCP to the backend"
          ],
          "packageName": "dnsdist",
          "product": "DNSdist",
          "programFiles": [
            "dnsdist-tcp-downstream.cc"
          ],
          "repo": "https://github.com/PowerDNS/pdns",
          "vendor": "PowerDNS",
          "versions": [
            {
              "lessThan": "1.9.15",
              "status": "affected",
              "version": "1.9.0",
              "versionType": "semver"
            },
            {
              "lessThan": "2.0.7",
              "status": "affected",
              "version": "2.0.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "security@open-xchange.com"
    }
  ],
  "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."
    }
  ],
  "id": "CVE-2026-40209",
  "lastModified": "2026-06-25T15:59:47.100",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "security@open-xchange.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-40209",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-06-25T13:56:17.791790Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-06-25T13:16:39.527",
  "references": [
    {
      "source": "security@open-xchange.com",
      "url": "https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html"
    }
  ],
  "sourceIdentifier": "security@open-xchange.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-772"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}


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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.