National Security Advisor Michael Waltz looks at his phone as he prepares for a TV interview at the White House on May 01, 2025 in Washington, DC.
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The messaging app that President Donald Trump’s former national security advisor was seen using during a Cabinet meeting last week is temporarily suspending services following a reported hack, its parent company said Monday.
“TeleMessage is investigating a potential security incident,” a spokesperson for Smarsh, which runs the app, told CNBC in a statement. “Upon detection, we acted quickly to contain it and engaged an external cybersecurity firm to support our investigation.”
“Out of an abundance of caution, all TeleMessage services have been temporarily suspended. All other Smarsh products and services remain fully operational,” the spokesperson said.
The potential hack of TeleMessage, an Israel-founded app that acts as a modified version of the encrypted messenger Signal, was first reported Sunday by the tech news site 404 Media.
Data stolen by the hacker includes contents of messages sent using TeleMessage’s versions of Signal, WhatsApp, Telegram and WeChat, according to 404 Media.
The hacker has not obtained the messages of Trump’s then-national security advisor, Mike Waltz, or the people he spoke to, 404 Media reported.
The White House did not immediately respond to CNBC’s request for comment on the temporary suspension of TeleMessage services. It has defended the use of Signal within the administration, saying the app is approved for official use and comes loaded onto government phones.
But Trump had previously discouraged officials in his administration from using Signal in the wake of the leak controversy dubbed “Signalgate,” when Waltz accidentally added a journalist to a private discussion of pending military plans.
“I think we learned: Maybe don’t use Signal, okay?” Trump said in an interview with The Atlantic last month.
Trump’s comments were published two days before Wednesday’s Cabinet meeting, when Waltz was photographed with TeleMessage open on his phone.
The photo taken of Waltz indicated he was communicating with Vice President JD Vance, Secretary of State Marco Rubio, director of national intelligence Tulsi Gabbard and special envoy Steve Witkoff.
One day after the Cabinet meeting, Trump announced he will nominate Waltz to be the U.S. ambassador to the United Nations.
Rubio, who already serves as secretary of state, acting administrator of the U.S. Agency for International Development and acting archivist of the United States, will serve as interim national security advisor until the post is filled, Trump said.
Part of the Signalgate controversy involved questions about whether the messages in that private thread were being automatically erased, potentially implicating federal records-retention laws.
TeleMessage markets itself as a way for government agencies and businesses to adhere to those laws by making backup copies of chats.
But 404 Media reported last week that TeleMessage could undermine Signal’s end-to-end encryption — which protects the privacy of messages — because “the messages can be later retrieved after being stored somewhere else.”
A Signal spokesperson told NBC News on Friday, “We cannot guarantee the privacy or security properties of unofficial versions of Signal.”
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