JetFormBuilder — Dynamic Blocks Form Builder: Cross-site scripting
An unauthenticated attacker can craft a link whose query value feeds a text field configured with a query_var Dynamic Preset. A published form must render that field through a data-jfb-macro or JFB_FIELD macro. The value reaches browser HTML without sufficient escaping, enabling reflected DOM XSS when a victim follows the link. Affected versions: <= 3.6.6. The matching official changelog confirms 3.6.6.1 as fixed for this CVE.
- Component
- JetFormBuilder — Dynamic Blocks Form Builder
- Plugin slug
jetformbuilder- Affected
- <= 3.6.6
- Safe version
3.6.6.1- Published
- Oct 10, 2026
This CVE was published Oct 10, 2026 and is one of 25 known issues for this plugin.
Update, patch or deactivate.
Update to 3.6.6.1 or a later supported release. Application-level remediation: Treat macro values as text, constrain allowed preset sources, and apply context-aware sanitization after macro expansion.
A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.
Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.
Technical 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.
CVE / CNA vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N