SOPlanning before 1.47 has Incorrect Access Control because certain secret key information, and the related authentication algorithm, is public. The key for admin is hardcoded in the installation code, and there is no key for publicsp (which is a guest account).
SoPlanning before 1.47 doesn't correctly check the security key used to publicly share plannings. It allows a bypass to get access without authentication.
SOPlanning 1.45 is vulnerable to authenticated SQL Injection that leads to command execution via the users parameter, as demonstrated by export_ical.php.