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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-3986

MEDIUM · 6.4 CVSS v3.1 Published 2026-03-13
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
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
The Calculated Fields Form plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the form settings in all versions up to, and including, 5.4.5.0. This is due to insufficient capability checks on the form settings save handler and insufficient input sanitization of the `fcontent` field in `fhtml` field types. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

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 Calculated Fields Form WordPress plugin versions up to 5.4.5.0 contain a Stored XSS vulnerability in the form settings functionality. The vulnerability stems from two issues: insufficient capability checks allowing Contributor-level users to modify form settings, and lack of sanitization on the `fcontent` field within `fhtml` field types. Attackers can inject malicious JavaScript that executes when users access pages containing the compromised form.

MitigationUpdate the plugin to a version beyond 5.4.5.0 when available. In the interim, review user permissions and audit existing forms for injected scripts. Consider restricting Contributor-level access to form editing until the patch is applied.

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

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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. Verify plugin version
    In WordPress admin, go to Plugins > Installed Plugins, locate 'Calculated Fields Form', and note the version number displayed
    Affected if Version is 5.4.5.0 or lower
  2. Identify users with form editing capabilities
    In WordPress admin, go to Users > All Users and review which users have the Contributor role or higher who might have access to the plugin's form builder
    Affected if Contributor-level users have access to create or edit forms
  3. Locate forms containing fhtml field types
    Access the plugin form editor, open each existing form, and inspect the field list for any fields of type 'fhtml'
    Affected if Any form contains fhtml field types
  4. Inspect fcontent values for malicious scripts
    Within each fhtml field, locate the 'fcontent' parameter or content area and examine the raw HTML for script tags, iframe elements, event handlers, or suspicious encoded content
    Affected if The fcontent field contains unsanitized HTML with script tags, iframes, or JavaScript event handlers

A user is affected if the plugin version is 5.4.5.0 or lower AND Contributor-level users can access form editing AND any form contains fhtml fields with unsanitized content in the fcontent parameter

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

Update the plugin to a version beyond 5.4.5.0 when available. In the interim, review user permissions and audit existing forms for injected scripts. Consider restricting Contributor-level access to form editing until the patch is applied.

Recommended fix Moderate confidence

Latest version of Calculated Fields Form plugin (higher than 5.4.5.0)

  1. Log in to the WordPress admin dashboard
  2. Navigate to Plugins > Installed Plugins
  3. Find the 'Calculated Fields Form' plugin
  4. Click 'Update now' if an update is available, or manually upload the latest version from wordpress.org/plugins/calculated-fields-form
  5. After updating, verify the version number reflects a version higher than 5.4.5.0
  6. Test that form functionality works correctly, particularly forms using fhtml field types
Caveat Minor: Review any form configurations using fhtml field types after upgrade to ensure proper rendering

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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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-2026-3986 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
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