Blue Magic Board (BMB) is nice forum system written by https://bmforum.com
Some file error and show fullpath. I test newest version, maybe all older versions are infected.

https://domain.ext/[bmb_path]/footer.php
https://domain.ext/[bmb_path]/header.php
https://domain.ext/[bmb_path]/include/db/db_mysql_error.php
https://domain.ext/[bmb_path]/datafile/langlist.php
https://domain.ext/[bmb_path]/datafile/sendmail.php
https://domain.ext/[bmb_path]/datafile/style.php

This was reported Admin but haven't received reply yet.