Answer in brief
CVE-2026-100151 records a Medium severity (CVSS 6.1) vulnerability in Ninja Forms <= 3.15.5 - Reflected DOM-Based Cross-Site Scripting via 'querystring:<key>' URL Parameter. The current sources do not mark it as known exploited. The current feed maps kstover/Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps kstover/Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| kstover/Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Buildergeneric | >=0 <=3.15.5 | Not reported |
Published upstream
Oct 31, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 31, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 31, 2026
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.
Quoted source text, attributed separately from HOL analysis.