How severe is CVE-2021-43066?

CVE-2021-43066 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2021-43066 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43066?

CVE-2021-43066 affects Fortinet Forticlient. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43066?

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-2021-43066 published?

CVE-2021-43066 was published on 2022-05-11 and last updated on 2026-06-17.

CVE-2021-43066

CVE-2021-43066 is a high-severity vulnerability in Fortinet Forticlient with a CVSS 3.x base score of 8.4. 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-668.

Key facts

Severity: High (CVSS 3.x base score 8.4)
CVSS v2: 4.6
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-668
Affected product: Fortinet Forticlient
Published: 2022-05-11
Last modified: 2026-06-17

Description

A external control of file name or path in Fortinet FortiClientWindows version 7.0.2 and below, version 6.4.6 and below, version 6.2.9 and below, version 6.0.10 and below allows attacker to escalate privilege via the MSI installer.

Frequently asked questions

What is CVE-2021-43066?: A external control of file name or path in Fortinet FortiClientWindows version 7.0.2 and below, version 6.4.6 and below, version 6.2.9 and below, version 6.0.10 and below allows attacker to escalate privilege via the MSI installer.
How severe is CVE-2021-43066?: CVE-2021-43066 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2021-43066 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43066?: CVE-2021-43066 affects Fortinet Forticlient. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43066?: 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-2021-43066 published?: CVE-2021-43066 was published on 2022-05-11 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-21-154

Affected products (1)

cpe:2.3:a:fortinet:forticlient:*:*:*:*:*:windows:*:*

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