CVE-2026-3906

WordPress core is vulnerable to unauthorized access in versions 6.9 through 6.9.1. The Notes feature (block-level collaboration annotations) was introduced in WordPress 6.9 to allow editorial comments directly on posts in the block editor. However, the REST API `create_item_permissions_check()` method in the comments controller did not verify that the authenticated user has `edit_post` permission on the target post when creating a note. This makes it possible for authenticated attackers with Subscriber-level access to create notes on any post, including posts authored by other users, private posts, and posts in any status.

More information : https://core.trac.wordpress.org/browser/trunk/src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php#L562