Vulnerability · Published Oct 31, 2026 · Assigned by Wordfence

CVE-2026-100151Ninja Forms <= 3.15.5 - Reflected DOM-Based Cross-Site Scripting via 'querystring:<key>' URL Parameter

Medium 6.1

In plain English

A medium-severity cross-site scripting in Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder from kstover. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 14% of all known vulnerabilities).

Severity (CVSS 3.1)6.1Medium

Exploit odds (30 days)0.2%top 86.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

The Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder plugin for WordPress is vulnerable to Reflected DOM-Based Cross-Site Scripting via 'querystring:<key>' URL 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 execute if they can successfully trick a user into performing an action such as clicking on a link. This bypass is triggered when an attacker supplies a matching field:<key> URL parameter that causes the server to fully resolve the {field:*} placeholder, forcing the client-side else-branch to abandon the server-sanitized value and reconstruct field content from the raw query string.

Affected products (as reported)

Vendor	Product	Versions
kstover	Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder	0 – through 3.15.5

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

In plain English

Official description

Affected products (as reported)

References