Usermin is a web-based interface for webmail, password changing, mail filters, fetchmail and much more. It is designed for use by regular non-root users on a Unix system, and limits them to tasks that they would be able to perform if logged in via SSH or at the console.
It is possible for a malicious user to view any file on the server, including root owned files, by creating a hardlink under the user accessible mail directory which will then be rendered within Usermin.
This vulnerability is rated as HIGH due to the fact that sensitive information can be obtained.
This vulnerability was tested against Usermin 1.630.
This vulnerability was patched in Usermin 1.640.