The Sync Post With Other Site WordPress plugin before 1.9.3 does not correctly enforce the page-editing capability on a REST route that creates and updates posts, because of an operator-precedence flaw in its authorization check. An authenticated user holding only the post-editing capability (such as a Contributor) can create, publish, and overwrite arbitrary Pages, including modifying content authored by higher-privileged users.
https://wpscan.com/vulnerability/cc635e60-f80e-4399-a016-9fde9228c58c/