{"id":"CVE-2026-103646","title":"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-acc…","summary":"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-acc…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-287"],"product":"Ultimate Multisite","affected":["ultimate_multisite < 2.17.0"],"published":"2026-10-08","updated":"2026-10-08","sourceUpdated":"2026-10-08T20:51:18.123","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-103646","references":[{"url":"https://wpscan.com/vulnerability/a05da0ad-5d92-406f-b182-b3ed1f8389f3/","label":"contact@wpscan.com"}],"tags":["nvd","cve.org"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-08T10:58:10.240709Z"},"ingestedAt":"2026-10-08T07:18:54.835Z","epss":0.00357,"epssPercentile":0.29264,"slug":"CVE-2026-103646","body":"## Overview\n\nThe 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":217963,"id":"CVE-2026-103646","ts":1791459563948,"field":"cvss","old":null,"new":"9.8"},{"seq":217962,"id":"CVE-2026-103646","ts":1791459563948,"field":"severity","old":"none","new":"critical"}]}