The PublishPress Revisions: Duplicate Posts, Submit, Approve and Schedule Content Changes plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 3.5.15 via the 'actAjaxRevisionDiffs' function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to extract sensitive data including revisions of posts and pages.
https://plugins.trac.wordpress.org/changeset/3192492/
https://plugins.trac.wordpress.org/browser/revisionary/trunk/admin/history_rvy.php#L322
https://github.com/publishpress/PublishPress-Revisions/blob/master/admin/history_rvy.php#L322