# Gutenberg Blocks – PublishPress Blocks Controls, Visibility, Reusable Blocks <= 3.7.6 - Authenticated (Contributor+) Stored Cross-Site Scripting via Lightbox Data Attributes

- **ID:** WPSEC-2026-3106
- **Plugin:** PublishPress Blocks – Block Controls, Block Visibility, Block Permissions (`advanced-gutenberg`), https://wordpress.org/plugins/advanced-gutenberg/
- **Affected versions:** from 3.3.2 before 3.7.7
- **Fixed in:** 3.7.7 (Update to 3.7.7 or later.)
- **Severity:** Medium 6.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N)
- **Weakness:** CWE-79
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-11-13)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/advanced-gutenberg
- **Fix released:** 2026-11-12
- **Published:** 2026-11-13
- **URL:** https://wpsec.com/vuln/WPSEC-2026-3106/

## Description

The PublishPress Blocks plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'data-cbox-*' lightbox attributes in post content in all versions from 3.3.2 up to, and including, 3.7.6. This is due to insufficient input sanitization: WordPress allows data-* attributes in post content, and the bundled Colorbox library reads its options, such as 'html' and 'title' (and 'open', which opens the lightbox on page load), from these attributes on the plugin's lightbox elements and renders them as HTML. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

## References

- https://wpsec.com/vuln/WPSEC-2026-3106/
- https://plugins.svn.wordpress.org/advanced-gutenberg/tags/3.7.7/
- https://wordpress.org/plugins/advanced-gutenberg/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-3106/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.