# CVE-2026-118800: aBlocks Gutenberg Blocks stored cross-site scripting in headingTag

Source: https://junglewise.ai/threats/cve-2026-118800-the-ablocks-gutenberg-blocks-user-dashboard-builder-popup  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-07. Updated: 2026-11-07  
License: CC BY 4.0 with a link back

CVE-2026-118800 · Severity: medium · CVSS 6.4 · Published 2026-11-07

aBlocks is a WordPress plugin that extends the editor with custom blocks for building pages and forms. An authenticated attacker with contributor-level access or higher can inject malicious scripts into pages through the heading block's headingTag parameter, causing those scripts to execute when other users view the affected pages.

Technologies: [aBlocks – Gutenberg Blocks, User Dashboard Builder, Popup Builder, Form Builder & Animation Builder](https://junglewise.ai/threats/technologies/ablocks-gutenberg-blocks-user-dashboard-builder-popup-builder-form-builder-animation-builder). Vendors: [aBlocks](https://junglewise.ai/threats/vendors/ablocks).

## Quick answers

**Is CVE-2026-118800 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-118800 being exploited in the wild.

**How severe is CVE-2026-118800?** Medium severity, with a CVSS score of 6.4, published 7 November 2026.

**Which products and versions are affected?** aBlocks – Gutenberg Blocks, User Dashboard Builder, Popup Builder, Form Builder & Animation Builder up to and including 2.18.0.

**Is there a fix for CVE-2026-118800?** 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-2026-118800 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-118800?** Check whether you run aBlocks – Gutenberg Blocks, User Dashboard Builder, Popup Builder or Form Builder & Animation Builder 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 plugin fails to sanitize the 'headingTag' parameter in the heading block before storing it to the database, resulting in stored cross-site scripting (XSS). An attacker with contributor-level privileges or above can inject arbitrary JavaScript that persists and executes in the browsers of all users who access the affected page. A fix exists in versions after 2.18.0.

## Affected products

- aBlocks aBlocks – Gutenberg Blocks, User Dashboard Builder, Popup Builder, Form Builder & Animation Builder up to and including 2.18.0

## Timeline

- 2026-11-07: disclosed

## References

- [https://plugins.trac.wordpress.org/browser/ablocks/tags/2.18.0/includes/blocks/heading/block.php](https://plugins.trac.wordpress.org/browser/ablocks/tags/2.18.0/includes/blocks/heading/block.php)
- [https://plugins.trac.wordpress.org/browser/ablocks/tags/2.18.0/includes/blocks/heading/block.php](https://plugins.trac.wordpress.org/browser/ablocks/tags/2.18.0/includes/blocks/heading/block.php)

## Related threats

- [aBlocks Gutenberg Blocks plugin sensitive information exposure via shortcode](https://junglewise.ai/threats/cve-2026-118801-the-ablocks-gutenberg-blocks-user-dashboard-builder-popup)
- [aBlocks Gutenberg Blocks privilege escalation in form-builder endpoint](https://junglewise.ai/threats/cve-2026-110018-the-ablocks-gutenberg-blocks-user-dashboard-builder-popup)