CVE-2021-43076Public exploitNetwork attack vector

System-file modification via unrestricted fnsysctl shell

Published Sep 6, 2022 · Updated Oct 22, 2024

Improper privilege management in Fortinet FortiADC 6.2.1 and earlier allows remote authenticated users to modify system files. The web console exposes the fnsysctl Unix command to restricted profiles, allowing FTP uploads and file moves into system paths. A restricted account with web-console shell access is sufficient to replace files, alter the administrative interface, and change appliance behavior.

CVSS severity6.5
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper privilege management in Fortinet FortiADC 6.2.1 and earlier allows remote authenticated users to modify system files. The web console exposes the fnsysctl Unix command to restricted profiles, allowing FTP uploads and file moves into system paths. A restricted account with web-console shell access is sufficient to replace files, alter the administrative interface, and change appliance behavior.

The record

CVE
CVE-2021-43076
Published
Sep 6, 2022
Updated
Oct 22, 2024
Vendor
Fortinet
Product
FortiADC
Classifications
CWE-269, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 6, 2022CVE publishedPublication date reported by the CVE source.
  2. Oct 22, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=FortiADC 6.2.1, 6.2.0, 6.1.5, 6.1.4, 6.1.3, 6.1.2, 6.1.1, 6.1.0, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0, 5.4.5, 5.4.4, 5.4.3, 5.4.2, 5.4.1, 5.4.0, 5.3.7, 5.3.6, 5.3.5, 5.3.4, 5.3.3, 5.3.2, 5.3.1, 5.3.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Fortinet · FortiADCversion=FortiADC 6.2.1, 6.2.0, 6.1.5, 6.1.4, 6.1.3, 6.1.2, 6.1.1, 6.1.0, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0, 5.4.5, 5.4.4, 5.4.3, 5.4.2, 5.4.1, 5.4.0, 5.3.7, 5.3.6, 5.3.5, 5.3.4, 5.3.3, 5.3.2, 5.3.1, 5.3.0

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
6.2FortinetCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:F/RL:X/RC:X
6.3FortinetCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-269Improper Privilege Management
T1565.001Stored Data Manipulation

Public exploit references

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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