Vulnerability-Lookup

FKIE_CVE-2026-52686

Vulnerability from fkie_nvd - Published: 2026-07-23 09:16 - Updated: 2026-07-23 09:16

Severity

3.7 (Low) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Summary

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.

References

	URL	Tags
	security@open-xchange.com	https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-10.html

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://repo.powerdns.com/",
          "defaultStatus": "unaffected",
          "modules": [
            "DNSSEC validation"
          ],
          "packageName": "pdns-recursor",
          "product": "Recursor",
          "programFiles": [
            "syncres.cc"
          ],
          "repo": "https://github.com/PowerDNS/pdns",
          "vendor": "PowerDNS",
          "versions": [
            {
              "lessThan": "5.2.12",
              "status": "affected",
              "version": "5.2.0",
              "versionType": "semver"
            },
            {
              "lessThan": "5.3.9",
              "status": "affected",
              "version": "5.3.0",
              "versionType": "semver"
            },
            {
              "lessThan": "5.4.4",
              "status": "affected",
              "version": "5.4.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "security@open-xchange.com"
    }
  ],
  "cveTags": [],
  "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."
    }
  ],
  "id": "CVE-2026-52686",
  "lastModified": "2026-07-23T09:16:26.967",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 3.7,
          "baseSeverity": "LOW",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 1.4,
        "source": "security@open-xchange.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-23T09:16:26.967",
  "references": [
    {
      "source": "security@open-xchange.com",
      "url": "https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-10.html"
    }
  ],
  "sourceIdentifier": "security@open-xchange.com",
  "vulnStatus": "Received"
}

CVE-2026-52686 (GCVE-0-2026-52686)

Vulnerability from cvelistv5 – Published: 2026-07-23 08:03 – Updated: 2026-07-23 13:56

Title

Wildcard CNAME proof validation bypass

Summary

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.

Severity

3.7 (Low)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

Insufficient Verification of Data Authenticity
CWE-347 - Improper Verification of Cryptographic Signature

Assigner

References

1 reference

URL	Tags
https://docs.powerdns.com/recursor/security-advis…

Impacted products

1 product

Vendor	Product	Version
PowerDNS	Recursor	Affected: 5.2.0 , < 5.2.12 (semver) Affected: 5.3.0 , < 5.3.9 (semver) Affected: 5.4.0 , < 5.4.4 (semver)

Date Public

2026-07-21 22:00

Credits

Qifan Zhang from Palo Alto Networks

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-52686",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-23T13:56:39.271508Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-347",
                "description": "CWE-347 Improper Verification of Cryptographic Signature",
                "lang": "en",
                "type": "CWE"
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        "providerMetadata": {
          "dateUpdated": "2026-07-23T13:56:55.653Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://repo.powerdns.com/",
          "defaultStatus": "unaffected",
          "modules": [
            "DNSSEC validation"
          ],
          "packageName": "pdns-recursor",
          "product": "Recursor",
          "programFiles": [
            "syncres.cc"
          ],
          "repo": "https://github.com/PowerDNS/pdns",
          "vendor": "PowerDNS",
          "versions": [
            {
              "lessThan": "5.2.12",
              "status": "affected",
              "version": "5.2.0",
              "versionType": "semver"
            },
            {
              "lessThan": "5.3.9",
              "status": "affected",
              "version": "5.3.0",
              "versionType": "semver"
            },
            {
              "lessThan": "5.4.4",
              "status": "affected",
              "version": "5.4.0",
              "versionType": "semver"
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          ]
        }
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          "type": "finder",
          "value": "Qifan Zhang from Palo Alto Networks"
        }
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          ],
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      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 3.7,
            "baseSeverity": "LOW",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
            "version": "3.1"
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          "scenarios": [
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              "value": "GENERAL"
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      "problemTypes": [
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          "descriptions": [
            {
              "description": "Insufficient Verification of Data Authenticity",
              "lang": "en",
              "type": "CWE"
            }
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        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-23T08:03:37.563Z",
        "orgId": "8ce71d90-2354-404b-a86e-bec2cc4e6981",
        "shortName": "OX"
      },
      "references": [
        {
          "url": "https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-10.html"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Wildcard CNAME proof validation bypass",
      "x_generator": {
        "engine": "Vulnogram 1.0.4"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8ce71d90-2354-404b-a86e-bec2cc4e6981",
    "assignerShortName": "OX",
    "cveId": "CVE-2026-52686",
    "datePublished": "2026-07-23T08:03:37.563Z",
    "dateReserved": "2026-06-08T08:05:31.707Z",
    "dateUpdated": "2026-07-23T13:56:55.653Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

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FKIE_CVE-2026-52686

CVE-2026-52686 (GCVE-0-2026-52686)

Tags

Sightings

Nomenclature