dbcve.org
Formidable Form BuilderWordPress extension · Strategy11

CVE-2019-15780

CRITICAL · 9.8 CVSS v3.1 Published 2019-08-29
Fix available
A fix is available. Upgrade to 4.02.01 or later.
See remediation →
100/100
Remediation priority · Urgent
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 formidable plugin before 4.02.01 for WordPress has unsafe deserialization.

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 Formidable WordPress plugin before version 4.02.01 contains an unsafe deserialization vulnerability. Deserialization vulnerabilities can allow attackers to manipulate serialized data to execute arbitrary code, potentially leading to complete site compromise.

MitigationUpgrade the Formidable plugin to version 4.02.01 or later to remediate the unsafe deserialization 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
Formidable Form BuilderWordPress extension
Affected:< 4.02.01

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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. Verify Formidable plugin is installed
    Check for the existence of the Formidable plugin directory at /wp-content/plugins/formidable/ or look for Formidable in the WordPress plugins admin page
    Affected if Formidable plugin is not present in the WordPress installation
  2. Identify the installed Formidable version
    Open the main plugin file (typically /wp-content/plugins/formidable/formidable.php) and locate the Version header in the plugin comment block, or check the version in the WordPress plugins admin list
    Affected if The version displayed is lower than 4.02.01 (for example, 4.02.00, 4.01.x, etc.)
  3. Confirm the plugin is active
    Check the WordPress plugins admin page or the wp_options table for the option 'active_plugins' to see if Formidable is enabled
    Affected if The plugin is active and the version is below 4.02.01
  4. Check for deserialization entry points
    Review if the plugin settings or any custom code passes user-supplied data through PHP unserialize() function - look for calls to unserialize() in the plugin files under /wp-content/plugins/formidable/
    Affected if The plugin version is below 4.02.01 AND contains unserialize() calls handling external input

The environment is affected if the Formidable Form Builder plugin is installed with a version lower than 4.02.01 and is actively in use.

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 4.02.01 or later
Fixed in 4.02.01
Interim mitigation

Upgrade the Formidable plugin to version 4.02.01 or later to remediate the unsafe deserialization vulnerability.

Recommended fix High confidence

Formidable Form Builder version 4.02.01 or latest available version

  1. 1. Create a full backup of your WordPress site (database and files) before updating
  2. 2. Log in to the WordPress admin dashboard
  3. 3. Navigate to Plugins > Installed Plugins
  4. 4. Locate 'Formidable Form Builder' in the plugin list
  5. 5. If an update is available, click 'Update Now' to upgrade to version 4.02.01 or later
  6. 6. Alternatively, download the fixed version from wordpress.org and upload it via Plugins > Add New > Upload Plugin
  7. 7. After updating, verify the plugin version shows 4.02.01 or higher
  8. 8. Test that forms continue to function correctly

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

Fix this in Formidable Form Builder Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2019-15780 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2019-15780 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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