dbcve.org
Improper Input ValidationWeakness · CWE-20

CVE-2024-13666

MEDIUM · 5.3 CVSS v3.1 Published 2025-03-22
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges 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
The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to IP Address Spoofing in all versions up to, and including, 5.2.12 due to insufficient IP address validation and use of user-supplied HTTP headers as a primary method for IP retrieval. This makes it possible for unauthenticated attackers spoof their IP address and submit forms that may have IP-based restrictions.

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

The Fluent Forms plugin for WordPress uses user-supplied HTTP headers (e.g., X-Forwarded-For, X-Real-IP) as the primary method to determine visitor IP addresses without validating that these headers actually came from a trusted proxy. This allows unauthenticated attackers to submit arbitrary IP addresses in these headers to bypass IP-based restrictions on forms.

MitigationImplement validation to ensure HTTP headers are only trusted from known proxy sources (e.g., load balancers), or use server-side REMOTE_ADDR as the primary IP source with proper handling for trusted reverse proxies only.

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

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
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 Fluent Forms installation
    Check for the Fluent Forms plugin directory in wp-content/plugins/ or view installed plugins in WordPress admin under Plugins
    Affected if Fluent Forms plugin is present in the WordPress installation
  2. Determine Fluent Forms version
    Read the main plugin file (fluentform.php) or check the plugin version in WordPress admin Plugins list
    Affected if Installed version falls within the vulnerable range (any version using unvalidated HTTP headers for IP detection)
  3. Verify IP detection uses unvalidated headers
    Examine the plugin source code for usage of $_SERVER['X-Forwarded-For'] or $_SERVER['X-Real-IP'] without checking for trusted proxy sources
    Affected if Code references these headers without validating they came from a trusted reverse proxy
  4. Check for IP-based form restrictions
    Review form settings in Fluent Forms admin for any IP blocking, rate limiting, or submission restrictions based on IP
    Affected if Any IP-based restrictions are configured on forms

The environment is affected if Fluent Forms is installed and uses X-Forwarded-For or X-Real-IP headers without validating proxy trust, especially if IP-based form restrictions are in place.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement validation to ensure HTTP headers are only trusted from known proxy sources (e.g., load balancers), or use server-side REMOTE_ADDR as the primary IP source with proper handling for trusted reverse proxies only.

Recommended fix Moderate confidence

Upgrade to Fluent Forms version 5.2.13 or later (latest stable version)

  1. Log in to the WordPress admin dashboard
  2. Navigate to Plugins > Installed Plugins
  3. Locate Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder
  4. Check the current version installed
  5. If the installed version is 5.2.12 or earlier, click 'Update now' to upgrade to the latest version
  6. Alternatively, download the latest version from wordpress.org/plugins/fluentform/ and upload via Plugins > Add New > Upload Plugin
  7. After update, verify the version number reflects the latest release

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

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.

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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-2024-13666 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