Reddit: Outsider can affect Upvote Percentage of private subreddit post by calling /api/vote API

Summary: Attacker that does not have access to a private subreddit, can still affect Upvote Percentage of any posts in this private subreddit. He does that by calling /api/vote API and passing post id directly. What is Upvote Percentage?: F1407175 Impact: - Attacker can affect Upvote Percentage o...