Latest Posts on sidebar showing future posts

I have my sidebar set to show the ten latest posts. When looking at my stats tonight, I realized someone had viewed a post that I have set to publish on Monday. After some looking around, I realized that future posts are showing up in the sidebar, in the list of latest posts, and are accessible to users by clicking on that link, despite not being “published” yet. Can someone tell me how I might fix this? I went back and set my future posts as drafts in the meantime.

Thanks!