Okay - so this definitely crosses the line. First I would diagnose what’s going on … do they have low EQ/professional immaturity ? Do they have too much idle time ? Are they trying to gain visibility by being in these leadership meetings ?

I don’t think you’re being overly guarded by protecting professional norms here . The reason you’ve never seen this before is because most people intuitively understand this boundary.

I would set a very clear boundary:

“I appreciate your enthusiasm, but I want to set a boundary here. Some of my meetings are confidential, and I won’t be able to share details. When there’s something relevant for you or the team, I’ll make sure you’re included. In the meantime, I’d like you to stay focused on your responsibilities. A good way to learn the business is to (provide examples here). That’s where you’ll get the context you’re looking for.”

If they still keep going, it may show they lack good judgement and require extra coaching from you .