PhpWiki is an open source content management system written in PHP.
Harold Hallikainen has reported that the Upload page fails to properly check the extension of a file.
A remote attacker could upload a specially crafted PHP file to the vulnerable server, resulting in the execution of arbitrary PHP code with the privileges of the user running PhpWiki.
There is no known workaround at this time.
All PhpWiki users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=www-apps/phpwiki-1.3.10-r3"