I've upgraded to the latest version (non-BETA) of our Forum system SMF. Here is announcement made by SMF admins:
Simple Machines is happy to announce the release of SMF 1.1.6, which fixes a number of minor bugs in 1.1.5 and addresses a security vulnerability. While the vulnerability primarily affects SMF installations on Windows servers, we would like to encourage all users to upgrade as soon as possible. A successful exploit could result in privilege escalation.