CVE-2026-6394
MediumWhat is CVE-2026-6394?
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.
CVSS Vector Breakdown
CVSS 3.1Exploitable remotely over the network without requiring access to the local system.
Exploit requires specific conditions, timing, or configuration to succeed.
No authentication required. Any anonymous user can exploit this vulnerability.
No user interaction required. Exploit runs without any victim action.
Exploiting the vulnerability can affect other components beyond the vulnerable one.
Some sensitive information is disclosed, but attacker has limited access.
Attacker can modify some data, but scope or consequence is limited.
No availability impact. Service remains fully operational.
FAQ
CVE-2026-6394 has a CVSS score of 5.4/10, rated as Medium. Review the affected products list and apply vendor patches.
CVSS (Common Vulnerability Scoring System) rates vulnerability severity from 0.0 to 10.0. CVE-2026-6394 scores 5.4/10 (Medium). Scores 9.0–10.0 are Critical, 7.0–8.9 are High, 4.0–6.9 are Medium, and below 4.0 are Low.
The list of devices confirmed to be affected by CVE-2026-6394 is shown in the "Affected Devices" section above. Check your firmware version against the vendor security advisory and apply the latest patch.
Apply the latest firmware or software update from the vendor. Check the References section above for official advisories and patch notes. If no patch is available, consider disabling the affected feature or isolating the device from untrusted networks.