The Atlantic's editor-in-chief Jeffrey Goldberg revealed the security breach in a first-hand account detailing how Trump 's national security adviser, Mike Waltz, mistakenly invited him into the chat on Signal, a publicly available encrypted messaging app.

Editor-in-chief of The Atlantic, Jeffrey Goldberg, wrote Monday that there were 18 people in the group chat discussing the attack plans, including users he identified as national security adviser Michael Waltz, Vice President JD Vance, Secretary of Defense Pete Hegseth, CIA director John Ratcliffe and others.