The WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) plugin for WordPress is vulnerable to Authentication Bypass via OIDC Nonce Replay in all versions up to, and including, 44.1 This is due to Id_Token_Service_Deprecated::process_openidconnect_token() using the incompatible WordPress core wp_verify_nonce() function to validate a nonce produced by Nonce_Service::create_nonce() — a 64-character hex value that wp_verify_nonce() can never successfully verify — causing the nonce check to silently fail without terminating authentication, so execution continues into authenticate_oidc_user() with the attacker-supplied id_token. This makes it possible for unauthenticated attackers who have obtained a previously-issued, valid id_token for a target account to replay that token and authenticate as any WordPress user, including administrators, resulting in full site takeover. This vulnerability is only exploitable when the use_id_token_parser_v2 plugin option is enabled, as this is the configuration that routes token processing through the deprecated parser containing the broken nonce check.