Oversharing 

When someone shares private things (they have with someone else) with others outside the "circle" without consent.

He was oversharing

Oversharing by Im7 October 20, 2023

Pushy-overhearer 

Japanese slang word rooted in Shangaya district of Tokyo. Means intrusive someone who pries into other people's lives.

Man Bob is such a pushy-overhearer

I know he never stops getting into other people's business.

Pushy-overhearer by Don'tyousee April 19, 2018