view_all_bug_page.php in MantisBT 2.10.0-development before 2018-02-02 allows remote attackers to discover the full path via an invalid filter parameter, related to a filter_ensure_valid_filter call in current_user_api.php.
If, after successful installation of MantisBT through 2.5.2 on MySQL/MariaDB, the administrator does not remove the 'admin' directory (as recommended in the "Post-installation and upgrade tasks" section of the MantisBT Admin Guide), and the MySQL client has a local_infile setting enabled (in php.ini mysqli.allow_local_infile, or the MySQL client config file, depending on the PHP setup), an attacker may take advantage of MySQL's "connect file read" feature to remotely access files on the MantisBT server.