The Simple Restrict WordPress plugin before 1.2.9 does not enforce its content-restriction permission check on the REST API the way it does on the front end, relying there on a generic capability check instead of the Simple Restrict WordPress plugin before 1.2.9's own permission system, allowing users with contributor-level access or above to read the content of restricted posts and pages they were never granted access to.

The Simple Restrict WordPress plugin before 1.2.9 does not enforce its content-restriction permission check on the REST API the way it does on the front end, relying there on a generic capability check instead of the Simple Restrict WordPress plugin before 1.2.9's own permission system, allowing users with contributor-level access or above to read the content of restricted posts and pages they were never granted access to.