# CVE-2026-103912: JetFormBuilder DOM-based cross-site scripting in query_var preset

Source: https://junglewise.ai/threats/cve-2026-103912-the-jetformbuilder-dynamic-blocks-form-builder-plugin-for  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-10. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-103912 · Severity: medium · CVSS 4.7 · Published 2026-10-10

JetFormBuilder is a form-building plugin for WordPress that allows site owners to create dynamic forms. The plugin is vulnerable to reflected DOM-based cross-site scripting (XSS), allowing attackers to inject malicious scripts that execute in a visitor's browser if they click a malicious link. This could lead to session hijacking, credential theft, or malware distribution targeting site visitors.

Technologies: [Crocoblock JetFormBuilder](https://junglewise.ai/threats/technologies/jetformbuilder). Vendors: [Crocoblock](https://junglewise.ai/threats/vendors/crocoblock).

## Quick answers

**Is CVE-2026-103912 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-103912 being exploited in the wild.

**How severe is CVE-2026-103912?** Medium severity, with a CVSS score of 4.7, published 10 October 2026.

**Which products and versions are affected?** Crocoblock JetFormBuilder up to and including 3.6.6.

**Is there a fix for CVE-2026-103912?** 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-2026-103912 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-103912?** Check whether you run Crocoblock JetFormBuilder 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 vulnerability is a reflected DOM-based XSS in the query_var preset functionality caused by insufficient input sanitization and output escaping. Unauthenticated attackers can inject arbitrary JavaScript through attacker-controlled query parameters that match a form's configured query_var setting, particularly when a text field is configured with a Dynamic Preset and referenced via data-jfb-macro or JFB_FIELD:: macros. Exploitation requires tricking a user into clicking a crafted link on a page containing a vulnerable form.

## Affected products

- CrocoBlock JetFormBuilder up to and including 3.6.6

## Timeline

- 2026-10-10: disclosed

## References

- [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/assets/build/frontend/main.js)
- [https://plugins.trac.wordpress.org/browser/jetformbuilder/tags/3.6.6/includes/presets/sources/preset-source-query-var.php](https://plugins.trac.wordpress.org/browser/jetformbuilder/tags/3.6.6/includes/presets/sources/preset-source-query-var.php)

## Related threats

- [Crocoblock JetFormBuilder stored cross-site scripting](https://junglewise.ai/threats/cve-2026-123482-improper-neutralization-of-input-during-web-page-generation)
- [Crocoblock JetFormBuilder cross-site scripting vulnerability](https://junglewise.ai/threats/cve-2026-123484-improper-neutralization-of-input-during-web-page-generation)
- [Crocoblock JetFormBuilder content injection in form pages](https://junglewise.ai/threats/cve-2026-123860-improper-neutralization-of-script-related-html-tags-in-a-web)
- [Crocoblock JetFormBuilder stored XSS in form fields](https://junglewise.ai/threats/cve-2026-123483-improper-neutralization-of-script-related-html-tags-in-a-web)
- [JetFormBuilder Stored Cross-Site Scripting via form field mapping](https://junglewise.ai/threats/cve-2026-119183-the-jetformbuilder-dynamic-blocks-form-builder-plugin-for)