I work as a software engineer in a software-only company, and I have found confidential information about a contract between my company and a client online. The document that I have found was on the server of one of our clients. I found it because I had to look up one of their installations and used google to do so. (They run at multiple web addresses and I used a google search to get the right one).
When doing this, I found out that they have a confidential document of my company publicly available. The document clearly states that it is confidential. It states the pricing information about the product we have made for them, such as development cost, installation cost, maintenance cost etc.
What could I do about this? Should I mention it to someone higher up in my company first? Or perhaps if the file were confidential for the client, the client could still decide it was okay to put it online.
As a note: I do not know how easy it is to find the document on their website. It just came up as the fourth result on google when looking for them.