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FortiproxyApplication · Fortinet

CVE-2021-43081

MEDIUM · 6.1 CVSS v3.1 Published 2022-05-11
Fix available
A fix is available. Upgrade to 2.0.8 / 6.4.9 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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
An improper neutralization of input during web page generation vulnerability [CWE-79] in FortiOS version 7.0.3 and below, 6.4.8 and below, 6.2.10 and below, 6.0.14 to 6.0.0. and in FortiProxy version 7.0.1 and below, 2.0.7 to 2.0.0 web filter override form may allow an unauthenticated attacker to perform an XSS attack via crafted HTTP GET 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

A reflected Cross-Site Scripting (XSS) vulnerability in the web filter override form of FortiOS and FortiProxy allows unauthenticated attackers to inject malicious JavaScript via crafted HTTP GET requests due to improper input neutralization.

MitigationUpgrade to FortiOS versions 7.0.4, 6.4.9, 6.2.11, 6.0.15 or later, and FortiProxy versions 7.0.2, 2.0.8 or later to remediate this vulnerability.

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
FortiproxyApplication
Affected:>= 2.0.0, < 2.0.8>= 7.0.0, < 7.0.2
FortiosOperating system
Affected:>= 6.0.0, <= 6.0.14>= 6.2.0, <= 6.2.10>= 6.4.0, < 6.4.9>= 7.0.0, < 7.0.4

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
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

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 Fortinet product type
    Determine whether the device is running FortiOS or FortiProxy by consulting device documentation or checking the system information via CLI command 'get system status'
    Affected if Device is running FortiOS or FortiProxy
  2. Check FortiOS version
    Run CLI command 'get system status' or 'FGV' to retrieve the installed FortiOS version number
    Affected if FortiOS version is 6.0.0 through 6.0.14, 6.2.0 through 6.2.10, 6.4.0 through 6.4.8, or 7.0.0 through 7.0.3
  3. Check FortiProxy version
    Run CLI command 'get system status' or consult the web UI to retrieve the installed FortiProxy version number
    Affected if FortiProxy version is 2.0.0 through 2.0.7 or 7.0.0 through 7.0.1
  4. Confirm web filter override form accessibility
    Verify that the web filter override feature is enabled and accessible. In FortiOS, check via CLI 'get webfilter profile' or via the web UI under Security Profiles > Web Filter to see if override is configured
    Affected if The web filter override form is accessible to unauthenticated or low-privilege users via HTTP GET requests

The environment is affected if the device runs FortiOS version 6.0.0-6.0.14, 6.2.0-6.2.10, 6.4.0-6.4.8, or 7.0.0-7.0.3, OR FortiProxy version 2.0.0-2.0.7 or 7.0.0-7.0.1, and the web filter override form is accessible.

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 2.0.8 / 6.4.9 / 7.0.2 or later
Fixed in 2.0.86.4.97.0.2
Interim mitigation

Upgrade to FortiOS versions 7.0.4, 6.4.9, 6.2.11, 6.0.15 or later, and FortiProxy versions 7.0.2, 2.0.8 or later to remediate this vulnerability.

Recommended fix High confidence

FortiOS: 6.0.15+, 6.2.11+, 6.4.9+, 7.0.4+ | FortiProxy: 2.0.8+, 7.0.2+

  1. 1. Identify the FortiOS or FortiProxy device in your environment and note its current version
  2. 2. For FortiOS 6.0.x: Upgrade to version 6.0.15 or later
  3. 3. For FortiOS 6.2.x: Upgrade to version 6.2.11 or later
  4. 4. For FortiOS 6.4.x: Upgrade to version 6.4.9 or later
  5. 5. For FortiOS 7.0.x: Upgrade to version 7.0.4 or later
  6. 6. For FortiProxy 2.0.x: Upgrade to version 2.0.8 or later
  7. 7. For FortiProxy 7.0.x: Upgrade to version 7.0.2 or later
  8. 8. Download the appropriate firmware from Fortinet support portal (fortinet.com/support)
Caveat Minor: Review release notes for any behavioral changes between versions; some older FortiOS 6.0 configurations may need adjustment when moving to newer branches

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

Fix this in Fortiproxy Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2021-43081 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