The GenerateBlocks plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 2.2.0. This is due to missing object-level authorization checks in the /wp-json/generateblocks/v1/dynamic-tag-replacements REST endpoint. The endpoint only verifies that the user has the edit_posts capability but does not verify the user has permission to access the specific post or its associated data referenced by attacker-controlled id parameters in dynamic tag content. This makes it possible for authenticated attackers, with Contributor-level access and above, to extract sensitive information from arbitrary posts including author email addresses and non-protected post meta values by crafting dynamic tag payloads such as {{post_meta id:<target>|key:<meta_key>}} and {{post_title id:<target>|link:author_email}}.