Wild Apricot Login <= 1.0.18 — Authentication Bypass via SSO Email-Collision Account Binding on Multisite

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Wild Apricot Login.
• No admin access? Run a passive check of your site. It reads public files only.

What to do

1. No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch Wild Apricot Login to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to zickzick2.

The Wild Apricot Login plugin for WordPress is vulnerable to Authentication Bypass via SSO Email-Collision Account Binding in all versions up to, and including, 1.0.18. When no WildApricot contact-ID mapping is found for an incoming SSO login, the plugin falls back to a network-global `get_user_by('email', ...)` lookup in `Module.php` to resolve a WordPress user, then `UserSynchronizer::syncWaContact()` binds and `Controller::login()` issues a session cookie via `wp_set_auth_cookie()` for that resolved user — both guarded only by `is_super_admin()` — without ever requiring proof of ownership of the matched WordPress account such as a password, local account-linking confirmation, inbox verification, or administrator approval. This makes it possible for attackers with custom-level WildApricot membership access to authenticate as an existing WordPress subsite administrator on a path-based Multisite network, obtaining a valid network-global authentication cookie for the victim without their credentials. Exploitation requires that the attacker control a WildApricot contact whose email address matches the target WordPress administrator's email — achievable via a public zero-fee membership application on the connected WildApricot organization — and that they complete the SSO flow on any subsite where Wild Apricot Login is active; because WordPress user identities and authentication cookies are network-global, the cookie issued on that subsite is equally valid on any other subsite where the victim user holds an administrator role.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

• Advisorywordfence.com

Timeline

1. Oct 28, 2026

   CVE published

   Severity high, CVSS 7.5

2. Nov 13, 2026

   Record last updated