Tosfos: Public knowledge is not lashon harah

Chofetz Chaim (clall 2) goes into great detail to try and disprove the simple understanding of Bava Basra (39b)/Erachin (16a), Tosfos and the view of the Rambam. These sources seem to say that the essence of lashon harah is speaking gossip in a concealed manner - not just saying negative things about others. Thus if it is said in a way that it will become public knowledge then there is no prohibition of lashon harah. This is apparently closer to the peshat of Vayikra (19:16).

Erachin(16a): Disparaging remarks said in front of three people is not considered lashon harah. What is the reaon? Because your friend has a friend and your friend’s friend has a friend [and thus it is considered public knowledge].

Tosfos (Bava Basra 39b): Negative words about another person that are said n the presence of three people is not prohibited as lashon harah - either to say or to repeat it to others This is clarified by the statement said in Erachin (15b) There this statement is said in the context of R’ Yossi statement in which he said, “I have never said something and looked around to see who was listening.” That means he wasn’t concerned if the one he was talking about was there. [That proves that saying negative comments in the presence of three people is not considered lashon harah – Rashi].

Rambam(Hilchos De’os 7:5): Speaking lashon harah is prohibited whether the person being spoken about is present or not. Those words which will cause harm to another person - either physically or financially when repeated by others or even if it upset him or frightens him – is considered lashon harah. If these types of words are said in the presence of three people then it can be assumed that they have become public knowledge Therefore if one of the three repeats the negative words which he had heard on another occasion – there is no prohibition of lashon harah. However this is only permitted if he did not intend to spread the news and cause it to become more known.