phpBB is an Open Source bulletin board package.
phpBB is vulnerable to a cross-site scripting vulnerability due to improper sanitization of user supplied input. Coupled with poor validation of BBCode URLs which may be included in a forum post, an unsuspecting user may follow a posted link triggering the vulnerability.
Successful exploitation of the vulnerability could cause arbitrary scripting code to be executed in the browser of a user.
There are no known workarounds at this time.
All phpBB users should upgrade to the latest version:
emerge --sync emerge --ask --oneshot --verbose ">=www-apps/phpBB-2.0.15"