Is CVE-2026-100151 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-100151 being exploited in the wild.

How severe is CVE-2026-100151?

Medium severity, with a CVSS score of 6.1, published 31 October 2026.

Which products and versions are affected?

Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder up to and including 3.15.5.

Is there a fix for CVE-2026-100151?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-100151 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-100151?

Check whether you run Ninja Forms – Contact Form Builder with Calculators, Quizzes or Signatures & AI Form Builder at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-100151: Ninja Forms Contact Form Builder DOM-based XSS in URL parameter

CVE-2026-100151 · Severity: medium · CVSS 6.1 · Published 2026-10-31

Ninja Forms is a WordPress plugin used to build and manage contact forms. An unauthenticated attacker can inject malicious scripts into web pages by crafting a malicious link with specially crafted URL parameters; if a user clicks the link, the injected script executes in their browser, potentially stealing data or session tokens.

Vendors: Ninja Forms.

Quick answers

Is CVE-2026-100151 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-100151 being exploited in the wild.
How severe is CVE-2026-100151?: Medium severity, with a CVSS score of 6.1, published 31 October 2026.
Which products and versions are affected?: Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder up to and including 3.15.5.
Is there a fix for CVE-2026-100151?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-100151 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-100151?: Check whether you run Ninja Forms – Contact Form Builder with Calculators, Quizzes or Signatures & AI Form Builder at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The plugin is vulnerable to Reflected DOM-Based Cross-Site Scripting (XSS) via insufficient input sanitization and output escaping of 'querystring:<key>' URL parameters. When an attacker supplies a matching field:<key> URL parameter, the server-side sanitization is bypassed and the client-side JavaScript reconstructs field content directly from the raw query string, allowing arbitrary script injection. The vulnerability affects all versions up to and including 3.15.5.

Affected products

Ninja Forms Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder up to and including 3.15.5

Timeline

2026-10-31: disclosed

References

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