How severe is CVE-2021-43037?

CVE-2021-43037 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-43037 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43037?

CVE-2021-43037 affects Kaseya Unitrends Backup. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43037?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-43037 published?

CVE-2021-43037 was published on 2021-12-06 and last updated on 2026-06-17.

CVE-2021-43037

CVE-2021-43037 is a high-severity vulnerability in Kaseya Unitrends Backup with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-427.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 6.9
EPSS exploit prediction: 1% (39th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-427
Affected product: Kaseya Unitrends Backup
Published: 2021-12-06
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-43037?: 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.
How severe is CVE-2021-43037?: CVE-2021-43037 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-43037 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43037?: CVE-2021-43037 affects Kaseya Unitrends Backup. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43037?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-43037 published?: CVE-2021-43037 was published on 2021-12-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:kaseya:unitrends_backup:*:*:*:*:*:*:*:*

More vulnerabilities in Kaseya Unitrends Backup

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