CVE-2026-19769

Ninja Forms <= 3.15.1 - Unauthenticated Stored Cross-Site Scripting via Repeater Child 'type' Confusion via Unmatched Array Key

2026-09-04 17:43
Jonah Burgess (CryptoCat)

Strategic Overview

Status
Patched in 3.15.2
Affected Plugin
Ninja Forms – The Contact Form Builder That Grows With You
Affected Version
<= 3.15.1
CVSS
7.2High
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2026-19769
View all Ninja Forms – The Contact Form Builder That Grows With You vulnerabilities

At a glance

CVE-2026-19769 is a high-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Ninja Forms WordPress plugin, affecting versions <= 3.15.1. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 3.15.2; sites on affected versions should update now. Disclosed September 2026, reported by Jonah Burgess (CryptoCat).

Vulnerability Overview

The Ninja Forms – The Contact Form Builder That Grows With You plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Repeater Child 'type' Confusion via Unmatched Array Key in all versions up to, and including, 3.15.1 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. Exploitation requires the Ninja Forms File Uploads add-on to be active, as the attack routes the unwhitelisted child entry through the File Uploads handler to write an attacker-supplied HTML file containing arbitrary JavaScript into any web-server-writable directory, including the site root, where it is served from the site's own origin.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Ninja Forms <= 3.15.1 carries this weakness at type, and reaching it takes no account at all. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Ninja Forms the fix is 3.15.2: builds <= 3.15.1 are affected, anything from 3.15.2 onward is not.

Remediation

Update to version 3.15.2, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Ninja Forms 3.15.2 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-19769https://www.wordfence.com/threat-intel/vulnerabilities/id/2330e381-7db3-4b79-8827-818d2ea954b5https://nvd.nist.gov/vuln/detail/CVE-2026-19769

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C