CVE-2026-5427: extendthemes kubio ai page builder Missing Authorization

Vulnerability summary

CVE-2026-5427 is a medium (CVSS 5.3) Missing Authorization vulnerability in extendthemes kubio ai page builder. EPSS estimates a 0.47% chance of exploitation in the next 30 days, higher than 39.2% of scored vulnerabilities. Fixed in 2.7.3.

Timeline

1. 17-04-2026
   PublishedVulnerability first disclosed.
2. 17-04-2026
   Last modifiedVulnerability information updated.

Description

The Kubio plugin for WordPress is vulnerable to Arbitrary File Upload in versions up to and including 2.7.2. This is due to insufficient capability checks in the kubio_rest_pre_insert_import_assets() function, which is hooked to the rest_pre_insert_{post_type} filter for posts, pages, templates, and template parts. When a post is created or updated via the REST API, Kubio parses block attributes looking for URLs in the 'kubio' attribute namespace and automatically imports them via importRemoteFile() without verifying the user has the upload_files capability. This makes it possible for authenticated attackers with Contributor-level access and above to bypass WordPress's normal media upload restrictions and upload files fetched from external URLs to the media library, creating attachment posts in the database.

• CWE-862Missing AuthorizationThe product does not perform an authorization check when an actor attempts to access a resource or perform an action.