Vulnerability-Lookup

UBUNTU-CVE-2026-52684 (CVE-2026-52684)

Vulnerability from osv_ubuntu – Published: 2026-07-23 09:16 – Updated: 2026-07-29 07:58 – Source website

Details

If the auth responds very slowly and the records expire in between, the capping of TTLs is not enforced for lack of data. This does not happen on regular resolve as then then the child records are used immediately if not expired and thus valid, or the records are expired, and in that case not used. So this case can only happen if almost expired records are used to refresh the authoritative NS records.

Severity

3.7 (Low)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-52684	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-52684	REPORT
	https://github.com/PowerDNS/pdns/pull/17748	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "pdns-recursor",
            "binary_version": "4.0.0~alpha2-2ubuntu0.1+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "pdns-recursor",
        "purl": "pkg:deb/ubuntu/pdns-recursor@4.0.0~alpha2-2ubuntu0.1+esm1?arch=source\u0026distro=esm-apps/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.7.3-1",
        "4.0.0~alpha1-1",
        "4.0.0~alpha1-2",
        "4.0.0~alpha2-2",
        "4.0.0~alpha2-2ubuntu0.1",
        "4.0.0~alpha2-2ubuntu0.1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "pdns-recursor",
            "binary_version": "4.1.1-2ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "pdns-recursor",
        "purl": "pkg:deb/ubuntu/pdns-recursor@4.1.1-2ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.0.6-1",
        "4.0.6-1build1",
        "4.0.7-1",
        "4.1.1-1",
        "4.1.1-1build1",
        "4.1.1-2",
        "4.1.1-2ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "pdns-recursor",
            "binary_version": "4.2.1-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "pdns-recursor",
        "purl": "pkg:deb/ubuntu/pdns-recursor@4.2.1-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.2.0-6",
        "4.2.1-1",
        "4.2.1-1build1",
        "4.2.1-1build2",
        "4.2.1-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "pdns-recursor",
            "binary_version": "4.6.0-1ubuntu1+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "pdns-recursor",
        "purl": "pkg:deb/ubuntu/pdns-recursor@4.6.0-1ubuntu1+esm1?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.4.2-3",
        "4.6.0-1ubuntu1",
        "4.6.0-1ubuntu1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "pdns-recursor",
            "binary_version": "4.9.3-1build3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "pdns-recursor",
        "purl": "pkg:deb/ubuntu/pdns-recursor@4.9.3-1build3?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.9.0-2",
        "4.9.1-4",
        "4.9.2-1",
        "4.9.2-1build1",
        "4.9.2-2",
        "4.9.3-1",
        "4.9.3-1build2",
        "4.9.3-1build3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "pdns-recursor",
            "binary_version": "5.3.5-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "pdns-recursor",
        "purl": "pkg:deb/ubuntu/pdns-recursor@5.3.5-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.2.4-2build2",
        "5.3.1-1",
        "5.3.3-1",
        "5.3.4-1",
        "5.3.4-1build1",
        "5.3.4-2",
        "5.3.5-1"
      ]
    }
  ],
  "aliases": [],
  "details": "If the auth responds very slowly and the records expire in between, the capping of TTLs is not enforced for lack of data. This does not happen on regular resolve as then then the child records are used immediately if not expired and thus valid, or the  records are expired, and in that case not used.  So this case can only happen if almost expired records are used to refresh the authoritative NS records.",
  "id": "UBUNTU-CVE-2026-52684",
  "modified": "2026-07-29T07:58:09Z",
  "published": "2026-07-23T09:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-52684"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-52684"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/PowerDNS/pdns/pull/17748"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-52684"
  ]
}

CVE-2026-52684 (GCVE-0-2026-52684)

Vulnerability from cvelistv5 – Published: 2026-07-23 07:49 – Updated: 2026-07-23 14:00

Title

Prefetch Feature Allows Persistent Ghost Domain Cache Poisoning Attack

Summary

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 · CISA-ADP (v2.0.3)

Decision recorded 2026-07-23 14:00 UTC

CWE

Time-of-check Time-of-use (TOCTOU) Race Condition

Assigner

OX mitre root

References

1 reference

URL	Tags
https://github.com/PowerDNS/pdns/pull/17748

Impacted products

1 product

Vendor	Product	Version
PowerDNS	Recursor	Affected: 0.0.0 , < 5.5.0 (semver)

Date Public

2026-07-19 22:00

Credits

Taofei Guo, Peking University. Qi Wang and JianJun Chen and Haixin Duan, Tsinghua University.

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-52684",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-23T14:00:08.322568Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-23T14:00:17.742Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://repo.powerdns.com/",
          "defaultStatus": "unaffected",
          "modules": [
            "Packet cache",
            "Record cache"
          ],
          "packageName": "pdns-recursor",
          "product": "Recursor",
          "programFiles": [
            "rec-packetcache.cc",
            "recursor_cache.cc"
          ],
          "repo": "https://github.com/PowerDNS/pdns",
          "vendor": "PowerDNS",
          "versions": [
            {
              "lessThan": "5.5.0",
              "status": "affected",
              "version": "0.0.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Taofei Guo, Peking University. Qi Wang and JianJun Chen and Haixin Duan, Tsinghua University."
        }
      ],
      "datePublic": "2026-07-19T22:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eIf the auth responds \u003cem\u003every\u003c/em\u003e slowly and the records expire in between, the capping of TTLs is not enforced for lack of data. This does not happen on regular resolve as then then the \nchild records are used immediately if not expired and thus valid, or the\n records \u003cem\u003eare\u003c/em\u003e expired, and in that case not used.  So this case \ncan only happen if almost expired records are used to refresh the \nauthoritative NS records.\u003c/p\u003e"
            }
          ],
          "value": "If the auth responds very slowly and the records expire in between, the capping of TTLs is not enforced for lack of data. This does not happen on regular resolve as then then the \nchild records are used immediately if not expired and thus valid, or the\n records are expired, and in that case not used.  So this case \ncan only happen if almost expired records are used to refresh the \nauthoritative NS records."
        }
      ],
      "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"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "Time-of-check Time-of-use (TOCTOU) Race Condition",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-23T07:49:04.336Z",
        "orgId": "8ce71d90-2354-404b-a86e-bec2cc4e6981",
        "shortName": "OX"
      },
      "references": [
        {
          "url": "https://github.com/PowerDNS/pdns/pull/17748"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Prefetch Feature Allows Persistent Ghost Domain Cache Poisoning Attack",
      "x_generator": {
        "engine": "Vulnogram 1.0.4"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8ce71d90-2354-404b-a86e-bec2cc4e6981",
    "assignerShortName": "OX",
    "cveId": "CVE-2026-52684",
    "datePublished": "2026-07-23T07:49:04.336Z",
    "dateReserved": "2026-06-08T08:05:31.707Z",
    "dateUpdated": "2026-07-23T14:00:17.742Z",
    "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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

UBUNTU-CVE-2026-52684 (CVE-2026-52684)

CVE-2026-52684 (GCVE-0-2026-52684)

Tags

Sightings

Nomenclature

Related by attack behaviour