CVE-2026-12949
CriticalCVSS 9.8Summary
The Wishlist Member plugin for WordPress up to version 3.34.1 is vulnerable to account takeover due to insufficient verification of data authenticity. The wpm_register() function validates the registration cookie only against the GET reg parameter while accepting POST mergewith and POST wpm_id parameters without verifying that the mergewith user ID references a temporary or incomplete registrant bound to the current registration transaction. This allows unauthenticated attackers to take over any existing WordPress account, including administrator accounts, by supplying an arbitrary user's numeric ID as the mergewith value, causing wp_update_user() to overwrite the target account's username, password, email address, first name, and last name with attacker-controlled values, while WordPress password and email change notification emails are explicitly suppressed.
Risk Assessment
An attacker can fully take over an administrator account, leading to complete privilege escalation and control over the entire WordPress installation. This can result in data theft, website defacement, or using the server for further attacks.
Recommendation
Immediately update the Wishlist Member plugin to the latest available version that includes the fix. If updating is not possible, consider temporarily disabling the plugin until the patch is applied.
Original NVD description (English source)
The Wishlist Member plugin for WordPress is vulnerable to Account Takeover via Insufficient Verification of Data Authenticity in versions up to and including 3.34.1. This is due to the wpm_register() function validating the registration cookie only against the GET reg parameter while accepting the POST mergewith and POST wpm_id parameters without verifying that the mergewith user ID references a temporary or incomplete registrant that is bound to the current registration transaction. This makes it possible for unauthenticated attackers to take over any existing WordPress account — including administrator accounts — by supplying an arbitrary user's numeric ID as the mergewith value, which causes wp_update_user() to overwrite the target account's username (additionally written via a direct $wpdb UPDATE), password, email address, first name, and last name with attacker-controlled values, while WordPress password and email change notification emails are explicitly suppressed. When wpm_id references a non-existent membership level, no role key is added to the update payload, causing wp_update_user() to preserve the target user's existing role — including administrator — making full privilege escalation a direct consequence of the takeover.