{"schemaVersion":3,"id":"CVE-2026-103646","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"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 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2.17.0","eol":null,"hubHref":"/vendor/unknown/ultimate_multisite"},{"vendor":"wordpress","product":"ultimate-multisite","name":"Ultimate Multisite – WordPress Multisite SaaS & WaaS Platform","label":"ultimate-multisite","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≤ 2.16.0 (fixed in 2.17.0)","noFixRecorded":false,"fixedIn":"2.17.0"}],"versionsText":"≤ 2.16.0 (fixed in 2.17.0)","eol":null,"hubHref":null}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://wpscan.com/vulnerability/a05da0ad-5d92-406f-b182-b3ed1f8389f3/","label":"wpscan.com/vulnerability/a05da0ad-5d92-406f-b182-b3ed1f8389f3/","hostname":"wpscan.com","tags":["Exploit","VDB Entry","Technical Description"]},{"url":"https://www.wordfence.com/threat-intel/vulnerabilities/id/d9bb5fdb-939c-4c94-aa4e-fe56b45add5f","label":"www.wordfence.com/threat-intel/vulnerabilities/id/d9bb5fdb-939c-4c94-aa4e-fe56b45add5f","hostname":"www.wordfence.com","tags":["Vendor 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