CVE-2021-43042: Kaseya Unitrends Backup

Critical severity, CVSS 9.8. EPSS: 3% chance of exploitation in the next 30 days.

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.

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.