Summary
The remote host is missing an update to the system as announced in the referenced advisory.
Solution
Update your system with the appropriate patches or software upgrades.
http://www.gulftech.org/03202004.php
http://www.phpbb.com/phpBB/viewtopic.php?t=183982
http://www.vuxml.org/freebsd/c551ae17-7f00-11d8-868e-000347dd607f.html
Insight
The following package is affected: phpbb