CVE-2021-43033: Kaseya Unitrends Backup

Critical severity, CVSS 9.8. EPSS: 6.2% chance of exploitation in the next 30 days.

An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5. Multiple functions in the bpserverd daemon were vulnerable to arbitrary remote code execution as root. The vulnerability was caused by untrusted input (received by the server) being passed to system calls.

Affected products

• Kaseya Unitrends Backup: from 10.0, before 10.5.5 (fixed in 10.5.5)

Published 2021-12-06. Last modified 2026-06-17.