CVE-2026-75957 (GCVE-0-2026-75957)

Vulnerability from cvelistv5 – Published: 2026-10-01 07:40 – Updated: 2026-10-01 13:42
VLAI
Title
Ultimate Multisite <= 2.15.0 - Unauthenticated Authentication Bypass via 'checkout_form' Parameter
Summary
The Ultimate Multisite – WordPress Multisite SaaS & WaaS Platform plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 2.15.0 via the `checkout_form` parameter of the `login_customer_after_checkout` function. This is due to the publicly accessible `wu_ajax_nopriv_wu_validate_form` AJAX handler accepting a freely obtainable checkout nonce, and the `checkout_form=wu-finish-checkout` parameter causing `get_validation_rules()` to discard all validation rules while `finish_checkout_form_fields()` returns an empty step list — forcing `is_last_step()` to return true and routing the request directly into full order processing — after which `maybe_create_customer()` resolves the attacker-supplied `email_address` to an existing WordPress user ID without any authentication or ownership verification, and `login_customer_after_checkout()` calls `wp_set_auth_cookie()` for that user ID via a passwordless code path. This makes it possible for unauthenticated attackers to log in as any existing WordPress user — including a Network Super Admin — simply by knowing their email address. Exploitation requires that the targeted user account has no pre-existing Ultimate Multisite customer record; accounts such as a Network Super Admin on a fresh Multisite install, or any administrator or editor added before Ultimate Multisite was configured, satisfy this condition and are therefore exploitable.
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 2026-10-01 13:40 UTC
CWE
  • CWE-287 - Improper Authentication
Assigner
Wordfence CNA under the mitre root
CNA scorecard C 65/100 over 2458 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
superdav42 Ultimate Multisite – WordPress Multisite SaaS & WaaS Platform Affected: 0 , ≤ 2.15.0 (semver)
guessed Create a notification for this product.
Credits
zickzick2
Show details on NVD website
To clipboard 

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}



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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.