How severe is CVE-2021-40386?

CVE-2021-40386 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-40386 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40386?

CVE-2021-40386 affects Kaseya Unitrends Backup. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40386?

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

When was CVE-2021-40386 published?

CVE-2021-40386 was published on 2022-04-15 and last updated on 2026-06-17.

CVE-2021-40386

CVE-2021-40386 is a critical-severity vulnerability in Kaseya Unitrends Backup with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Kaseya Unitrends Backup
Published: 2022-04-15
Last modified: 2026-06-17

Description

Kaseya Unitrends Client/Agent through 10.5,5 allows remote attackers to execute arbitrary code.

Frequently asked questions

What is CVE-2021-40386?: Kaseya Unitrends Client/Agent through 10.5,5 allows remote attackers to execute arbitrary code.
How severe is CVE-2021-40386?: CVE-2021-40386 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-40386 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40386?: CVE-2021-40386 affects Kaseya Unitrends Backup. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40386?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-40386 published?: CVE-2021-40386 was published on 2022-04-15 and last updated on 2026-06-17.

References

https://csirt.divd.nl/cves/CVE-2021-40386/

Affected products (1)

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

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