The rtMedia for WordPress, BuddyPress and bbPress WordPress plugin before 4.7.12 does not check ownership before changing the privacy level of an activity and its attached media, relying only on a nonce shared with every logged-in user, allowing users with a subscriber-level account or above to make another user's private activity public or hide it.
https://wpscan.com/vulnerability/58115528-18b6-4f2a-9f6c-d84fdcd6efb4/