What happened
The Simple Membership plugin for WordPress is vulnerable to unauthorized modification of data and sensitive information disclosure in versions up to, and including, 4.8.3 via the resend-activation and email-activation endpoints. The endpoints are dispatched from SwpmInitTimeTasks::check_and_do_email_activation() on frontend init with no authentication, nonce, capability, or ownership check, and the recipient address used by SwpmRegistration::send_reg_email() is taken from an attacker-controlled $_POST['email'] parameter (overriding the member's registered address). This makes it possible for unauthenticated attackers to redirect an arbitrary pending member's activation email — and the follow-up 'registration complete' email containing the member's username and plaintext password — to an attacker-chosen address, and to then activate that member's account without their consent.
Affected versions
Simple Membership: 0 through 4.8.3 (semver) Fixed: See vendor advisory.
Why it matters
Review the vendor advisory and exposure of the affected product to determine operational impact.
Detection & mitigation
- Apply vendor-provided updates or mitigations.
- Review affected product exposure and access logs.
Public PoC references
No public PoC reference has passed the current publication threshold.