I've been fighting this problem for several weeks now. I've updated Role Manager to the new one (not the owen winkler version), and it also does not fix the problem.
Everyone above subscriber can click "comments" and see everyone's comments, email addresses, and IP addresses. This is a very BAD thing.
From what I've read, edit_posts for contributor and authors is supposed to only display the person's own comments. However this function is broken somehow and instead anyone can see everyone else's comments.
Mark Jaquith says:
It wasn't designed to restrict people with edit_posts from only being able to see the comments they can edit. That would require a slight tweak in the code.
Is this a core code issue or a plugin issue? I think it is core code.
This is very important for me to resolve because i've had to demote everyone on my blog to subscriber, and nobody is able to post anymore.