CVE-2021-43204

Component denial of service via permission changes

Published Dec 9, 2021 · Updated Oct 25, 2024

Improper resource-lifetime control in Fortinet FortiClient Windows allows local users to stop client components by changing folder permissions. Affected releases are 6.4.0 through 6.4.1, 6.2.9 and earlier, and 6.0.10 and earlier; Fortinet does not identify the folder or internal lifecycle operation. Exploitation requires high local privileges and interrupts FortiClient components without reported confidentiality or integrity impact.

CVSS severity4.4
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper resource-lifetime control in Fortinet FortiClient Windows allows local users to stop client components by changing folder permissions. Affected releases are 6.4.0 through 6.4.1, 6.2.9 and earlier, and 6.0.10 and earlier; Fortinet does not identify the folder or internal lifecycle operation. Exploitation requires high local privileges and interrupts FortiClient components without reported confidentiality or integrity impact.

The record

CVE
CVE-2021-43204
Published
Dec 9, 2021
Updated
Oct 25, 2024
Vendor
Fortinet
Product
FortiClient Windows
Classifications
T1489
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Dec 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Oct 25, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=FortiClientWindows 6.4.1, 6.4.0, 6.2.9, 6.2.8, 6.2.7, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0, 6.0.10, 6.0.9, 6.0.8, 6.0.7, 6.0.6, 6.0.5, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0, 5.6.6, 5.6.5, 5.6.4, 5.6.3, 5.6.2, 5.6.1, 5.6.0, 5.4.5, 5.4.4, 5.4.3, 5.4.2, 5.4.1, 5.4.0, 5.2.6, 5.2.5, 5.2.4, 5.2.3, 5.2.2, 5.2.1, 5.2.0, 5.0.11, 5.0.10, 5.0.9, 5.0.8, 5.0.7, 5.0.6, 5.0.5, 5.0.4, 5.0.3, 5.0.2, 5.0.1, 5.0.0, 4.3.5, 4.3.4, 4.3.3, 4.3.2, 4.3.1, 4.3.0, 4.2.7, 4.2.6, 4.2.5, 4.2.4, 4.2.3, 4.2.2, 4.2.1, 4.2.0, 4.1.3, 4.1.2, 4.1.1, 4.1.0, 4.0.4, 4.0.3, 4.0.2, 4.0.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Fortinet · FortiClient Windowsversion=FortiClientWindows 6.4.1, 6.4.0, 6.2.9, 6.2.8, 6.2.7, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0, 6.0.10, 6.0.9, 6.0.8, 6.0.7, 6.0.6, 6.0.5, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0, 5.6.6, 5.6.5, 5.6.4, 5.6.3, 5.6.2, 5.6.1, 5.6.0, 5.4.5, 5.4.4, 5.4.3, 5.4.2, 5.4.1, 5.4.0, 5.2.6, 5.2.5, 5.2.4, 5.2.3, 5.2.2, 5.2.1, 5.2.0, 5.0.11, 5.0.10, 5.0.9, 5.0.8, 5.0.7, 5.0.6, 5.0.5, 5.0.4, 5.0.3, 5.0.2, 5.0.1, 5.0.0, 4.3.5, 4.3.4, 4.3.3, 4.3.2, 4.3.1, 4.3.0, 4.2.7, 4.2.6, 4.2.5, 4.2.4, 4.2.3, 4.2.2, 4.2.1, 4.2.0, 4.1.3, 4.1.2, 4.1.1, 4.1.0, 4.0.4, 4.0.3, 4.0.2, 4.0.1

Published CVSS scores

4.1FortinetCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C
4.9NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:C
4.4FortinetCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1489Service Stop

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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