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CVE-2026-52686

Status: Awaiting AnalysisLow (3.7)—

The issue is a DNSSEC validation bypass where wildcard expansion proofs (NSEC/NSEC3 records) are accepted without signature validation when the wildcard answer is a CNAME or DNAME record.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-52686",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-52686",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-07-23T13:56:39.271508Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security@open-xchange.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 3.7,
          "attackVector": "NETWORK",
          "baseSeverity": "LOW",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 2.2
      }
    ]
  },
  "affected": [
    {
      "source": "security@open-xchange.com",
      "affectedData": [
        {
          "repo": "https://github.com/PowerDNS/pdns",
          "vendor": "PowerDNS",
          "modules": [
            "DNSSEC validation"
          ],
          "product": "Recursor",
          "versions": [
            {
              "status": "affected",
              "version": "5.2.0",
              "lessThan": "5.2.12",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "5.3.0",
              "lessThan": "5.3.9",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "5.4.0",
              "lessThan": "5.4.4",
              "versionType": "semver"
            }
          ],
          "packageName": "pdns-recursor",
          "programFiles": [
            "syncres.cc"
          ],
          "collectionURL": "https://repo.powerdns.com/",
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-07-23T09:16:26.967",
  "references": [
    {
      "url": "https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-10.html",
      "source": "security@open-xchange.com"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-347"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The issue is a DNSSEC validation bypass where wildcard expansion proofs (NSEC/NSEC3 records) are accepted without signature validation when the wildcard answer is a CNAME or DNAME record."
    }
  ],
  "lastModified": "2026-07-23T15:48:25.133",
  "sourceIdentifier": "security@open-xchange.com"
}