Simple CSV Table <= 1.0.1 - Directory Traversal to Authenticated (Contributor+) Arbitrary File Read

The Simple CSV Table plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 1.0.1 via the `href` parameter in the `[csv]` shortcode. This is due to insufficient path validation before concatenating user-supplied input to a base directory path. This makes it possible for authenticated attackers, with Contributor-level access and above, to read the contents of arbitrary files on the server, which can contain sensitive information such as database credentials and authentication keys.