WPFunnels <= 3.12.8 - Authenticated (Funnel Manager+) Privilege Escalation via 'group_id' Path Parameter

The WPFunnels – Funnel Builder for WooCommerce with Checkout & One Click Upsell plugin for WordPress is vulnerable to Privilege Escalation via arbitrary option update in all versions up to, and including, 3.12.8. This is due to the update_settings() REST callback failing to validate the group_id path parameter against an allowlist of permitted option names before passing it directly to get_option() and update_option(), allowing the built-in wp_user_roles option — which satisfies the route's loose [\w-]+ regex — to be targeted. This makes it possible for authenticated attackers with the wpf_manage_funnels capability and above to elevate their privileges to administrator by writing a crafted role definition containing arbitrary capabilities into the wp_user_roles option, thereby granting any WordPress role full site administrator access. The wpf_manage_funnels capability is typically assigned to the Funnel Manager custom role created by the plugin, meaning this role is the minimum required to exploit the vulnerability.