My Safari Bookmarks & Favorites showing up on someone else’s iCloud device.

This has happened to me as well. All of my safari bookmarks & favorites showed up on my family member’s phone overnight. He lost all of his saved safari bookmarks and favorites, with all of mine appearing on his phone. We are absolutely not sharing Apple ID sign ins and we don’t do Family Sharing. I’d love to know how this happened. This is a pretty serious privacy issue.

this is happening to me and my daughter has her own Apple ID that was set up in the beginning. I never had to use mine. The only connection we have is that I have her under my family

I have not seen this happen on Family Sharing devices that use a different Apple ID. A quick search of the web just showed a couple of cases that turned out to be that they had the same Apple ID. Unless someone has had this happen and found a solution, the only thing I would suggest is to sign out of iCloud on both devices, then sign back in using the respective Apple ID's.

Please keep us posted, since this would be unintended behavior and a privacy concern.

I checked both devices, both were signed into their individual Apple IDs, which are very different. This happened overnight, and my phone was not on their WiFi network. Also, no software downloads happened that night.

Hoping to find another possibility as I can tell you for sure this happened and not signed into the same Apple ID. All of my safari fave and bookmarks showed up on my family member’s phone. He doesn’t have access to my Apple ID, not sure he even knows what that is (this is my elderly father who isn’t tech savvy at all). I didn’t have anything on my phone he shouldn’t have seen, but he is a Chevelle car enthusiast and lost three pages of cars he was looking at, to purchase one of them. It was very strange. I cannot figure it out thus far. Any tips or help is appreciated!

That can only happen if logged into the same Apple ID

What you describe is not possible unless logged into the same Apple ID, or unless the links were shared.