US Homeland Security Probes Cyber Breach in Sensitive Data Network
The U.S. Department of Homeland Security (DHS) said on Thursday (July 2, 2026) that it is investigating a recent cyber breach involving an unclassified information-sharing network.
In a statement, DHS described the incident as a “recent cyber incident” affecting an “unclassified legacy information sharing environment.” The department did not provide further details and did not respond to follow-up questions.
The breach is believed to have affected the Homeland Security Information Network (HSIN), a platform used to share sensitive but unclassified data with partners, including foreign law enforcement, local authorities, and other organizations. This information was first reported by GovExec, which cited two unnamed sources familiar with the matter. According to these sources, the breach likely occurred between late May and early June.
U.S. Senator Mark Warner, the top Democrat on the Senate Intelligence Committee, said that while the information on the network is not classified, it is “highly sensitive” and its exposure risks national security. He called on DHS and the Justice Department to “thoroughly investigate” who breached the network and what information was compromised.
The investigation is ongoing, and DHS has not disclosed the extent of the breach or whether any data was accessed or stolen.
