Pentagon employees were notified as recently as a week ago not to use Signal for government communications due to security risks.
NPR's Tom Bowman reported Tuesday that all agency employees received an email a week before warning about vulnerabilities in the encrypted app, which was used by Defense Secretary Pete Hegseth and other leading national security officials to discuss war plans on March 15, with a journalist added to the group chat by national security adviser Mike Waltz, perhaps unknowingly.
"A vulnerability has been identified in the Signal messenger application," the email begins.
The Atlantic's editor-in-chief Jeffrey Goldberg reported on his being added to the group chat, which he said came as a surprise but was confirmed to him as real when the war plans under discussion were carried out about two hours later in Yemen.
“Up until the Hegseth text on Saturday, it was mainly procedural and policy texting," Goldberg said in an interview. "Then it became war plans, and to be honest, that sent a chill down my spine.”
Goldberg did not report on the specific plans, which he said included “operational details of forthcoming strikes on Yemen. But he said the information shared in the non-secure, commercially available app could have been used to "harm American military and intelligence personnel," if they had been intercepted by an adversary.
It's not clear who ordered the email to be sent out to others in the Department of Defense or whether the warning was related in any way to Goldberg's reporting, which came Monday afternoon, but Hegseth declared to others on the group chat to which he was privy that their communications were secure.
“We are currently clean on OPSEC,” Hegseth wrote, using the military acronym for operational security.
Tulsi Gabbard, the director of national intelligence, posted on X a day before Goldberg was added to the top-secret communications that classified information must be locked down under penalty of law.
"Any unauthorized release of classified information is a violation and will be treated as such," Gabbard posted March 14.