In Apache OpenMeetings 3.0.0 - 4.0.1, CRUD operations on privileged users are not password protected allowing an authenticated attacker to deny service for privileged users.
Apache OpenMeetings 1.0.0 uses not very strong cryptographic storage, captcha is not used in registration and forget password dialogs and auth forms missing brute force protection.
Apache OpenMeetings 1.0.0 is vulnerable to SQL injection. This allows authenticated users to modify the structure of the existing query and leak the structure of other queries being made by the application in the back-end.