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FortiwebApplication · Fortinet

CVE-2021-43073

HIGH · 8.8 CVSS v3.1 Published 2022-02-02
Fix available
A fix is available. Upgrade to 6.2.7 / 6.3.17 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A improper neutralization of special elements used in an os command ('os command injection') in Fortinet FortiWeb version 6.4.1 and 6.4.0, version 6.3.15 and below, version 6.2.6 and below allows attacker to execute unauthorized code or commands via crafted HTTP requests.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

FortiWeb versions 6.4.1, 6.4.0, 6.3.15 and below, and 6.2.6 and below contain an OS command injection vulnerability where improper neutralization of special elements in HTTP requests allows remote attackers to execute arbitrary operating system commands on the affected device.

MitigationApply the vendor-supplied patch by upgrading FortiWeb to a fixed version. If immediate patching is not possible, restrict network access to the FortiWeb management interface to reduce attack surface.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FortiwebApplication
Affected:>= 5.8.0, < 6.2.7>= 6.3.0, < 6.3.17>= 6.4.0, < 6.4.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify FortiWeb version
    Run the command 'get system status' in the FortiWeb CLI or check the FortiWeb web UI dashboard for the firmware version displayed.
    Affected if The displayed version falls within these ranges: 5.8.0 to 6.2.6, 6.3.0 to 6.3.15, or 6.4.0 to 6.4.1.
  2. Confirm management interface accessibility
    Verify whether the FortiWeb management interface (HTTP/HTTPS on port 80/443 or custom admin ports) is reachable from untrusted networks. Check network firewall rules or access control lists that permit external access to FortiWeb admin ports.
    Affected if The management interface is exposed to the internet or untrusted internal networks.
  3. Review HTTP access logs
    Examine FortiWeb HTTP access logs for unusual or suspicious HTTP request patterns, particularly requests containing shell metacharacters (such as ; | & $ ` or command sequences) in URI parameters or headers. Use the CLI command 'execute log filter category traffic' to enable detailed logging if not already active.
    Affected if There are HTTP requests in the logs that contain potential command injection payloads.
  4. Check for unauthorized command execution
    Review FortiWeb system event logs and audit logs for unexpected commands or configuration changes. Run 'execute log view' in the CLI and look for commands executed outside of normal administrative sessions.
    Affected if There are log entries showing command execution that was not performed by authorized administrators.

You are affected if your FortiWeb version is 5.8.0 through 6.2.6, 6.3.0 through 6.3.15, or 6.4.0 through 6.4.1, and the management interface is accessible to potential attackers.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.2.7 / 6.3.17 / 6.4.2 or later
Fixed in 6.2.76.3.176.4.2
Interim mitigation

Apply the vendor-supplied patch by upgrading FortiWeb to a fixed version. If immediate patching is not possible, restrict network access to the FortiWeb management interface to reduce attack surface.

Recommended fix High confidence

FortiWeb 6.4.2+ (or 6.3.17+ or 6.2.7+ depending on your branch)

  1. 1. Identify the current FortiWeb version by navigating to System > Status in the FortiWeb GUI or running 'get system status' in the CLI.
  2. 2. Determine which version branch is currently in use (5.8.x, 6.2.x, 6.3.x, or 6.4.x).
  3. 3. For FortiWeb 6.4.x: Upgrade to version 6.4.2 or later.
  4. 4. For FortiWeb 6.3.x: Upgrade to version 6.3.17 or later.
  5. 5. For FortiWeb 6.2.x: Upgrade to version 6.2.7 or later.
  6. 6. For FortiWeb 5.8.x: Upgrade to version 6.2.7 or later (recommended to jump to a supported major version).
  7. 7. Download the upgrade firmware from the Fortinet Customer Support Portal: https://support.fortinet.com/
  8. 8. Back up the FortiWeb configuration before upgrading.
Caveat Review FortiWeb release notes for your target version to check for configuration or feature changes that may require adjustment.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fortiweb Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-43073 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data