An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5. A buffer overflow existed in the vaultServer component. This was exploitable by a remote unauthenticated attacker.
https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-2
https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-1