House subcommittee presses for investigation after officials shared sensitive operational details on Signal

Members of the House Oversight and Reform Committee’s Subcommittee on Military and Foreign Affairs pressed administration and outside witnesses on the national security implications of top officials using the Signal messaging app to share operational details before a military strike.

Ranking Member Subramanian opened the topic by describing media reports that a national security adviser “added a journalist to a signal group chat where top officials shared classified information about an upcoming strike,” and said the administration’s public statements that the material was not classified were insufficient. He asked for a “thorough review of our classification system” and for accountability and oversight.

Multiple members described the chat as reckless. Representative Stephen Lynch told the panel: “If you think that was a success, going on an insecure line in advance of a military operation and discuss openly on an insecure app the operational details of the forthcoming strikes … that was a colossal failure.” Representative Robert Garcia, among others, said senior officials who used an insecure channel to discuss sensitive operational details had endangered service members and should face consequences if rules were broken.

Witnesses agreed on technical limits and human risk. Professor Matt Blaze told members that end‑to‑end encryption protects data in transit but “if the cell phone is compromised, it doesn't matter what app you're using,” and that encrypted apps like Signal lack features required to manage classified information, such as ensuring recipients hold the necessary security clearances. Dr. Blaze said in open testimony that the easiest practical way for an attacker to obtain content on an encrypted app is to compromise endpoints rather than attempt to break the encryption in transit.

Committee members also pressed officials about the prevalence of using Signal and other third‑party apps by senior national security staff. Ranking Member Subramanian and others said they had not received a full accounting of whether private devices were compromised or how widely third‑party apps were used to discuss sensitive matters. Several members asked for an independent investigation and for the administration to provide corrective steps to prevent recurrence.

Members raised related oversight concerns about staffing at the Cybersecurity and Infrastructure Security Agency. Witnesses and some members said recent CISA personnel actions have reduced institutional capacity, which committee members warned could hamper federal ability to provide guidance and to coordinate with private industry.

The hearing ended without formal committee action but with multiple members saying they would pursue follow‑up oversight, seek secure briefings on the content and classification status of the messages, and pursue answers about whether officials followed existing protocols and whether corrective steps would be taken.

No witness or member provided evidence in the public hearing record that the private devices of the officials involved had been compromised; several witnesses said there is currently no public evidence one way or the other. Members entered several news articles into the record and asked the administration for investigations and briefings.