The vulnerability arises from insufficient sanitization of the colibri_blog_posts shortcode attributes, allowing attackers to inject arbitrary JavaScript that is stored in the database and rendered when a page containing the shortcode is viewed. This flaw corresponds to CWE‑79. The primary impact is that any user who visits the affected page will execute the injected script in their browser context, potentially leading to credential theft, session hijacking, defacement, or further lateral movement.

All versions of the Colibri Page Builder plugin up to and including 1.0.345 on WordPress installations are affected. The flaw is exploitable by any authenticated user with contributor level access or higher. Administrators of sites using these versions should assess whether contributors have access to publish or edit posts that can contain the shortcode.

The CVSS score for this issue is 6.4, indicating moderate severity. The EPSS score is less than 1%, implying that the likelihood of exploitation in the wild is low. It is not listed in the CISA KEV catalog. Exploitability requires an authenticated contributor account, so the attack vector is an authenticated administrative path. Attackers would craft a malicious shortcode, publish or edit a post, and the payload would be served to all users who view the page.