---
id: CVE-2026-109997
title: >-
  Ninja Forms <= 3.15.5 - Unauthenticated Stored Cross-Site Scripting via
  'extra' Parameter via Metadata Key Normalization
summary: >-
  The Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures &
  AI Form Builder plugin for WordPress is vulnerable to Stored Cross-Site
  Scripting via the 'formData.extra' parameter in all versions up to, and
  including, 3.1…
severity: high
cvss: 7.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N'
cvssSource: cna
cwe:
  - CWE-79
vendor: kstover
product: >-
  Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI
  Form Builder
affected:
  - >-
    ninja_forms_contact_form_builder_with_calculators_quizzes_signatures_ai_form_builder
    <= 3.15.5
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-01T17:34:59.887321Z'
published: '2026-10-31'
updated: '2026-11-01'
sourceUpdated: '2026-11-01T17:44:30.605Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-109997'
references:
  - url: >-
      https://www.wordfence.com/threat-intel/vulnerabilities/id/54da4deb-e50c-478d-ab99-222c5573a036?source=cve
  - url: >-
      https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/Templates/admin-metaboxes-calcs.html.php#L4
  - url: >-
      https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/AJAX/Controllers/Submission.php#L52
  - url: >-
      https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/AJAX/Controllers/Submission.php#L428
  - url: >-
      https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/Actions/Save.php#L311
  - url: >-
      https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/Database/Models/Submission.php#L731
  - url: >-
      https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/Admin/Metaboxes/Calculations.php#L23
  - url: 'https://wordpress.org/plugins/ninja-forms/'
  - url: >-
      https://plugins.trac.wordpress.org/changeset/3749135/ninja-forms/trunk/includes/Templates/admin-metaboxes-calcs.html.php
tags:
  - cve.org
epss: 0.00442
epssPercentile: 0.38584
ingestedAt: '2026-11-05T19:30:42.602Z'
---

## Overview

The Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'formData.extra' parameter in all versions up to, and including, 3.15.5 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The nf_ajax_submit endpoint issues a valid nonce to any requester on failure, effectively neutralizing the nonce check and making exploitation trivially achievable in a single unauthenticated request.

## Affected

- `ninja_forms_contact_form_builder_with_calculators_quizzes_signatures_ai_form_builder <= 3.15.5`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.