CVE-2026-109997
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.
Executive briefing
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Evidence confidence: Not assessed Evidence-derived, not an exploitability verdict
Severity & attack characteristics
CVSS vector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Technical explanation & impact
Technical root-cause details are not available in the current source record.
Assess the impact using the published CVSS metrics and the affected vendor component.
Affected products and versions
NVD has not supplied machine-readable vulnerable CPE product/version entries for this CVE. This is an information gap, not proof that no products are affected. Check the vendor advisory references below.
Remediation & validation
- Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
- Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
- Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
- Validate the remediation with a version check and vulnerability rescan, then retain change evidence.
No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.
Vendor advisories, patches & exploit references
- https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/AJAX/Controllers/Submission.php#L428 VENDOR security@wordfence.com
- https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/AJAX/Controllers/Submission.php#L52 VENDOR security@wordfence.com
- https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/Actions/Save.php#L311 VENDOR security@wordfence.com
- https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/Admin/Metaboxes/Calculations.php#L23 VENDOR security@wordfence.com
- https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/Database/Models/Submission.php#L731 VENDOR security@wordfence.com
- https://plugins.trac.wordpress.org/browser/ninja-forms/tags/3.15.5/includes/Templates/admin-metaboxes-calcs.html.php#L4 VENDOR security@wordfence.com
- https://plugins.trac.wordpress.org/changeset/3749135/ninja-forms/trunk/includes/Templates/admin-metaboxes-calcs.html.php VENDOR security@wordfence.com
- https://wordpress.org/plugins/ninja-forms/ VENDOR security@wordfence.com
- https://www.wordfence.com/threat-intel/vulnerabilities/id/54da4deb-e50c-478d-ab99-222c5573a036?source=cve REFERENCE security@wordfence.com