The Import and export users and customers plugin for WordPress is vulnerable to Privilege Escalation in all versions up to and including 2.0.8 via the `save_extra_user_profile_fields()` function. This is due to an incomplete blocklist that correctly restricts capability meta keys for the primary site (e.g., `wp_capabilities`, `wp_user_level`) but fails to block the equivalent meta keys for any other subsite in a WordPress Multisite network (e.g., `wp_2_capabilities`, `wp_2_user_level`), allowing these keys to pass the `in_array()` check and be written directly to user meta via `update_user_meta()`. This makes it possible for authenticated attackers, with Subscriber-level access and above, to escalate their privileges to Administrator on any subsite within the Multisite network by submitting a crafted profile update to `/wp-admin/profile.php`. Exploitation requires that an administrator has previously imported a CSV file containing multisite-prefixed capability column headers and has enabled the 'Show fields in profile?' option, which causes those keys to be stored in the `acui_columns` option and exposed as editable fields on the user profile page.
