How severe is CVE-2021-43204?

CVE-2021-43204 has a CVSS 3.x base score of 4.4, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-43204 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43204?

CVE-2021-43204 primarily affects Fortinet Forticlient. In total, 32 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-43204?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-43204 published?

CVE-2021-43204 was published on 2021-12-09 and last updated on 2026-06-17.

CVE-2021-43204

CVE-2021-43204 is a medium-severity vulnerability in Fortinet Forticlient with a CVSS 3.x base score of 4.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 4.4)
CVSS v2: 4.9
EPSS exploit prediction: 0% (27th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Fortinet Forticlient
Published: 2021-12-09
Last modified: 2026-06-17

Description

A improper control of a resource through its lifetime in Fortinet FortiClientWindows version 6.4.1 and 6.4.0, version 6.2.9 and below, version 6.0.10 and below allows attacker to cause a complete denial of service of its components via changes of directory access permissions.

Frequently asked questions

What is CVE-2021-43204?: A improper control of a resource through its lifetime in Fortinet FortiClientWindows version 6.4.1 and 6.4.0, version 6.2.9 and below, version 6.0.10 and below allows attacker to cause a complete denial of service of its components via changes of directory access permissions.
How severe is CVE-2021-43204?: CVE-2021-43204 has a CVSS 3.x base score of 4.4, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-43204 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43204?: CVE-2021-43204 primarily affects Fortinet Forticlient. In total, 32 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-43204?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43204 published?: CVE-2021-43204 was published on 2021-12-09 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-21-167

Affected products (32)

cpe:2.3:a:fortinet:forticlient:*:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.0.1:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.0.2:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.0.3:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.0.4:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.1.0:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.1.1:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.1.2:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.1.3:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.2.0:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.2.1:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.2.2:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.2.3:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.2.4:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.2.5:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.2.6:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.2.7:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.3.0:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.3.1:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.3.2:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.3.3:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.3.4:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:4.3.5:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:5.2.0:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:5.2.1:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:5.2.2:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:5.2.3:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:5.2.4:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:5.2.5:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:5.2.6:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:6.4.0:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:6.4.1:*:*:*:*:windows:*:*

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