Monstra CMS 3.0.4 allows users to upload arbitrary files, which leads to remote command execution on the server, for example because .php (lowercase) is blocked but .PHP (uppercase) is not.
Monstra 3.0.1 and earlier uses a cookie to track how many login attempts have been attempted, which allows remote attackers to conduct brute force login attacks by deleting the login_attempts cookie or setting it to certain values.