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.
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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Unknown | Ultimate Multisite | unaffected |
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Project Subscriptions
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Advisories
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Fixes
Solution
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Workaround
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References
History
Thu, 08 Oct 2026 06:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. 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. | |
| Title | Ultimate Multisite < 2.17.0 - Unauthenticated Authentication Bypass via 'email_address' Parameter | |
| References |
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Projects
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MITRE
Status: PUBLISHED
Assigner: WPScan
Published:
Updated: 2026-10-08T06:00:05.353Z
Reserved: 2026-10-01T06:42:15.491Z
Link: CVE-2026-103646
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-08T06:16:37.957
Modified: 2026-10-08T06:16:37.957
Link: CVE-2026-103646
Redhat
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OpenCVE Enrichment
No data.
Weaknesses
No weakness.