The vulnerability in the Yoast SEO plugin allows authenticated users with Contributor-level or higher access to retrieve SEO metadata from any post via the Meta Search REST API. The lack of ownership validation means a contributor can read sensitive information from posts owned by other users, including private and draft posts. This results in confidentiality loss rather than denial of service or code execution.

The issue affects the Yoast SEO plugin for WordPress on all versions up to and including 26.5. Users of Yoast SEO 26.5 or earlier are at risk. The plugin’s Meta Search endpoint does not enforce proper authorization for the 'post_id' parameter.

The CVSS base score of 4.3 indicates a moderate impact, but the vulnerability is exploitable only by authenticated accounts, limiting the threat surface. EPSS data is not available and the flaw is not listed in the CISA KEV catalog, suggesting that widespread exploitation is currently low. However, any site with contributors who need to view post content could be exposed to sensitive metadata leakage if they misuse the 'post_id' parameter.