§ 2511 Waiver of privilege by voluntary disclosure.

If you have a legal privilege that lets you keep certain information private, like conversations with your lawyer or doctor, you can lose that protection if you voluntarily share the information yourself. Once you tell someone else the private details, or agree to let someone else share them, you generally give up your right to keep that information confidential later on.

This applies to any major or meaningful part of the protected information, not just small details. For example, if you talk to your attorney about something private and then later tell a friend the same details, you may not be able to claim privilege over that information anymore if it comes up in court.

There is one exception. If the way you shared the information was itself protected by another privilege, then you have not waived anything. In that case, the original privilege still stands, because the disclosure did not happen in a way that exposed the information to the outside world.