The Advanced Members for ACF plugin for WordPress is vulnerable to Privilege Escalation in all…

Why it is Yellow

• CVSS 8.8 high

References

• https://plugins.svn.wordpress.org/advanced-members/trunk/
• https://plugins.trac.wordpress.org/browser/advanced-members/tags/1.3.0/acf/fields/base/trait-amem-field.php#L30
• https://plugins.trac.wordpress.org/browser/advanced-members/tags/1.3.0/acf/fields/class-user-password.php#L117
• https://plugins.trac.wordpress.org/browser/advanced-members/tags/1.3.0/core/actions/account.php#L227
• https://plugins.trac.wordpress.org/browser/advanced-members/tags/1.3.0/core/functions-forms.php#L105
• https://plugins.trac.wordpress.org/changeset/3779180/advanced-members/trunk/acf/fields/class-user-password.php
• https://www.wordfence.com/threat-intel/vulnerabilities/id/6fc38f0b-bf13-4d01-a4b3-38a43fc726d6?source=cve

Original description

The Advanced Members for ACF plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.3.0 via the `acf[_amem_local_user_password]` parameter of the `[advanced-members-account-password]` shortcode form submission. This is due to a PHP operator-precedence bug in the `pre_update_value` function of `acf/fields/class-user-password.php` that assigns boolean `true` instead of the resolved user ID to `$user_id`, causing the `_can_edit()` authorization check to pass for any logged-in user via PHP loose equality, and causing `wp_update_user()` to cast `'ID' => true` to integer `1` — unconditionally targeting the primary administrator account. This makes it possible for authenticated attackers, with Subscriber-level access and above, to overwrite the password of user ID 1 (the site's primary administrator) with an attacker-chosen value, granting full administrative access to the site. The intended exclusion guard in `Account::process` that strips the password field before saving is defeated because `amem_save_all_fields()` re-reads the full field list from `amem()->submission` and silently overwrites the caller-supplied excluded fields array with an empty array, ensuring the password field is always processed.