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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-103646
StatePUBLISHED
AssignerWPScan
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-08 06:16:37 UTC
Updated2026-10-08 06:16:37 UTC
DescriptionThe 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.

Risk And Classification

Problem Types: CWE-287 Improper Authentication

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Unknown Ultimate Multisite affected 2.17.0 semver Not specified

References

ReferenceSourceLinkTags
wpscan.com/vulnerability/a05da0ad-5d92-406f-b182-b3ed1f8389f3 [email protected] wpscan.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Erwan LR (WPScan) (en)

CNA: WPScan (en)

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