weMail < 2.0.8 - Sensitive Information Disclosure

Description

The plugin is vulnerable to authorization bypass due to the plugin's REST API trusting the `x-wemail-user` HTTP header to identify users without verifying the request originates from an authenticated WordPress session. This makes it possible for unauthenticated attackers who know or can guess an admin email (easily enumerable via `/wp-json/wp/v2/users`) to impersonate that user and access the CSV subscriber endpoints, potentially exfiltrating subscriber PII (emails, names, phone numbers) from imported CSV files.