{"schema":"threatline.record/2","record":{"id":"CVE-2026-103646","aliases":[],"summary":"Ultimate Multisite < 2.17.0 - Unauthenticated Authentication Bypass via 'email_address' Parameter","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.","categories":["Unclassified"],"product":"Ultimate Multisite","vendor":"Unknown","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-103646","source_modified_at":"2026-10-08T10:59:19.784Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"Ultimate Multisite","vendor":"Unknown","versions":[{"status":"affected","versionType":"semver","version":"0","lessThan":"2.17.0"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-103646","source_modified_at":"2026-10-08T10:59:19.784Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"Ultimate Multisite","ecosystem":null},"version":"2.17.0","basis":"first unaffected version stated in the CVE record"}],"cvss":9.8,"severity":"Critical","kev":{"listed":false},"epss":{"probability":0.00442,"percentile":0.37438,"score_date":"2026-10-23"},"published_at":"2026-10-08T06:00:05.353Z","modified_at":"2026-10-08T10:59:19.784Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-103646","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-08T10:59:19.784Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-103646","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://wpscan.com/vulnerability/a05da0ad-5d92-406f-b182-b3ed1f8389f3/","tags":["exploit","vdb-entry","technical-description"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CISA ADP","ssvc":{"exploitation":"none","automatable":"yes","technical_impact":"total","assessed_at":"2026-10-08T10:58:10.240709Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-08T10:59:19.784Z","content_hash":"3e40b9a5c17f3bef6e39890a23a2f8804339e234d11276f8e4705e6c2e7ec412"}}