Vulnerability-Lookup

GHSA-3QW6-7G4W-JH2G

Vulnerability from github – Published: 2026-10-08 06:31 – Updated: 2026-10-08 12:34

Details

The Ultimate Multisite WordPress plugin before 2.17.0 does not require authentication before a logged-out checkout is linked to, and logged in as, an existing WordPress account matching the submitted email address, and its duplicate-account check normalizes that address differently from the lookup used to create the customer, so an unauthenticated attacker can log in as any existing user, including a Network Super Admin, whose email address they know. This bypass is not addressed by the 2.15.1 fix for CVE-2026-75957 and remains exploitable in all versions up to and including 2.16.1, the releases that fix was expected to cover. Exploitation requires a checkout form configured without a password field (auto-generated password) and a target account that has no existing customer record in the Ultimate Multisite WordPress plugin before 2.17.0.

Severity

9.8 (Critical)


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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-103646"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-287"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-08T06:16:37Z",
    "severity": "CRITICAL"
  },
  "details": "The Ultimate Multisite  WordPress plugin before 2.17.0 does not require authentication before a logged-out checkout is linked to, and logged in as, an existing WordPress account matching the submitted email address, and its duplicate-account check normalizes that address differently from the lookup used to create the customer, so an unauthenticated attacker can log in as any existing user, including a Network Super Admin, whose email address they know.\nThis bypass is not addressed by the 2.15.1 fix for CVE-2026-75957 and remains exploitable in all versions up to and including 2.16.1, the releases that fix was expected to cover. Exploitation requires a checkout form configured without a password field (auto-generated password) and a target account that has no existing customer record in the Ultimate Multisite  WordPress plugin before 2.17.0.",
  "id": "GHSA-3qw6-7g4w-jh2g",
  "modified": "2026-10-08T12:34:22Z",
  "published": "2026-10-08T06:31:19Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-103646"
    },
    {
      "type": "WEB",
      "url": "https://wpscan.com/vulnerability/a05da0ad-5d92-406f-b182-b3ed1f8389f3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-103646 (GCVE-0-2026-103646)

Vulnerability from cvelistv5 – Published: 2026-10-08 06:00 – Updated: 2026-10-08 10:59

Title

Ultimate Multisite < 2.17.0 - Unauthenticated Authentication Bypass via 'email_address' Parameter

Summary

Severity

9.8 (Critical)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-08 10:58 UTC

CWE

CWE-287 Improper Authentication
CWE-287 - Improper Authentication

Assigner

WPScan CNA under the mitre root

CNA scorecard E 44/100 over 1506 records in the last 180 days details

References

1 reference

URL	Tags
https://wpscan.com/vulnerability/a05da0ad-5d92-40…	exploitvdb-entrytechnical-description

Impacted products

1 product

Vendor	Product	Version
Unknown	Ultimate Multisite	Affected: 0 , < 2.17.0 (semver)

Credits

Erwan LR (WPScan) WPScan

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.8,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-103646",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-08T10:58:10.240709Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-287",
                "description": "CWE-287 Improper Authentication",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-08T10:59:19.784Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Ultimate Multisite",
          "vendor": "Unknown",
          "versions": [
            {
              "lessThan": "2.17.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Erwan LR (WPScan)"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "WPScan"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The Ultimate Multisite  WordPress plugin before 2.17.0 does not require authentication before a logged-out checkout is linked to, and logged in as, an existing WordPress account matching the submitted email address, and its duplicate-account check normalizes that address differently from the lookup used to create the customer, so an unauthenticated attacker can log in as any existing user, including a Network Super Admin, whose email address they know.\nThis bypass is not addressed by the 2.15.1 fix for CVE-2026-75957 and remains exploitable in all versions up to and including 2.16.1, the releases that fix was expected to cover. Exploitation requires a checkout form configured without a password field (auto-generated password) and a target account that has no existing customer record in the Ultimate Multisite  WordPress plugin before 2.17.0."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-287 Improper Authentication",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-08T06:00:05.353Z",
        "orgId": "1bfdd5d7-9bf6-4a53-96ea-42e2716d7a81",
        "shortName": "WPScan"
      },
      "references": [
        {
          "tags": [
            "exploit",
            "vdb-entry",
            "technical-description"
          ],
          "url": "https://wpscan.com/vulnerability/a05da0ad-5d92-406f-b182-b3ed1f8389f3/"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Ultimate Multisite \u003c 2.17.0 - Unauthenticated Authentication Bypass via \u0027email_address\u0027 Parameter",
      "x_generator": {
        "engine": "WPScan CVE Generator"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1bfdd5d7-9bf6-4a53-96ea-42e2716d7a81",
    "assignerShortName": "WPScan",
    "cveId": "CVE-2026-103646",
    "datePublished": "2026-10-08T06:00:05.353Z",
    "dateReserved": "2026-10-01T06:42:15.491Z",
    "dateUpdated": "2026-10-08T10:59:19.784Z",
    "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.

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.

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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.

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GHSA-3QW6-7G4W-JH2G

CVE-2026-103646 (GCVE-0-2026-103646)

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