Executive brief
Kadence Blocks is a popular WordPress plugin used to enhance the website building experience. A security flaw in this plugin allows users with low-level access, such as contributors, to bypass security checks and upload unauthorized images to the website's media library. While this does not allow for full site takeover, it could be used to clutter server storage or host inappropriate content on the organization's infrastructure.
Technical details
The vulnerability is classified as a missing authorization check (CWE-862) within the `process_pattern` REST API endpoint of the Kadence Blocks plugin. The plugin fails to verify if the requesting user possesses the `upload_files` capability. An authenticated attacker with at least contributor-level permissions can exploit this by providing remote image URLs, which the server will then download and store as media attachments. This issue affects all versions up to and including 3.6.3; it was addressed in version 3.6.4.
Affected products
- StellarWP Kadence Blocks — Page Builder Toolkit for Gutenberg Editor up to, and including, 3.6.3
Timeline
- 2026-04-04: disclosed
- 2026-04-04: advisory