Codoforum 4.8.3 allows XSS in the user registration page: via the username field to the index.php?u=/user/register URI. The payload is, for example, executed on the admin/index.php?page=users/manage page.
The sanitize function in Codoforum 2.5.1 does not properly implement filtering for directory traversal sequences, which allows remote attackers to read arbitrary files via a .. (dot dot) in the path parameter to index.php.