CVE-2026-103646 (GCVE-0-2026-103646)

Vulnerability from cvelistv5 – Published: 2026-10-08 06:00 – Updated: 2026-10-08 10:59
VLAI
Title
Ultimate Multisite < 2.17.0 - Unauthenticated Authentication Bypass via 'email_address' Parameter
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-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.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-08 10:58 UTC
CWE
Assigner
WPScan CNA under the mitre root
CNA scorecard E 44/100 over 1506 records in the last 180 days details
References
URL Tags
https://wpscan.com/vulnerability/a05da0ad-5d92-40… exploitvdb-entrytechnical-description
Impacted products
Vendor Product Version CPE status
Unknown Ultimate Multisite Affected: 0 , < 2.17.0 (semver)
guessed Create a notification for this product.
Credits
Erwan LR (WPScan) WPScan
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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