What’s Vulnerable › Vulnerabilities

CVE-2021-43037

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-12-06 · updated 2026-06-17
• Weakness: CWE-427

Description

An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5. The Unitrends Windows agent was vulnerable to DLL injection and binary planting due to insecure default permissions. This allowed privilege escalation from an unprivileged user to SYSTEM.

Affected products

• Kaseya Unitrends Backup: from 10.0 before 10.5.5 — fixed in 10.5.5

How to fix

Upgrade to a fixed version: Kaseya Unitrends Backup 10.5.5. Check the vendor advisory for mitigations.

References

• https://helpdesk.kaseya.com/hc/en-gb/articles/4412762258961
• https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-1
• https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-2
• https://helpdesk.kaseya.com/hc/en-gb/articles/4412762258961
• https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-1
• https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-2

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