Nexa Blocks <= 1.1.1 — Unauthenticated Blind Server-Side Request Forgery via 'demo_json_file' Parameter

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Nexa Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE.
• No admin access? Run a passive check of your site. It reads public files only.
• No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

1. No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch Nexa Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Patryk Siewert.

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.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

• Advisorywordfence.com

Related CVEs

Timeline

1. May 19, 2026

   CVE published

   Severity medium, CVSS 5.4

2. Nov 13, 2026

   Record last updated