Ultimate Multisite < 2.17.0 - Unauthenticated Authentication Bypass via 'email_address' Parameter
- Published
- Last modified
- Status
- published
- Known exploitation
- Not listed in CISA KEV
- Fix
- Fixed in 2.17.0
- Public exploit
- None on Exploit-DB
- Exploitation: none
- Automatable: yes
- Technical impact: total
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Decision points from CISA's Vulnrichment, assessed (SSVC 2.0.3).
SSVC documentationSummary
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.
Affected versions
- Unknown Ultimate Multisite
fixed in 2.17.0