listmonk: SQL Injection in `/api/subscribers/export` bypasses table access control, leaking admin password hashes and SMTP credentials

listmonk is a standalone, self-hosted, newsletter and mailing list manager. Prior to 6.2.0, listmonk’s GET /api/subscribers/export endpoint injects the user-controlled query parameter into QuerySubscribersForExport in internal/core/subscribers.go without calling validateQueryTables, unlike GET /api/subscribers, allowing an authenticated user with subscribers:sql_query and subscribers:get_all to read arbitrary database tables such as users and settings and execute data-modifying PostgreSQL CTEs. This issue is fixed in version 6.2.0.