The Department of Homeland Security has confirmed that hackers broke into the Homeland Security Information Network (HSIN), a government platform used to share sensitive but unclassified threat intelligence between federal agencies, state and local governments, and private-sector security partners. The intrusion is believed to have taken place sometime between late May and early June 2026.
DHS says it “immediately isolated affected systems” and launched a forensic investigation. Officials have confirmed that no classified networks were impacted, but investigators have not yet determined whether any documents were stolen. HSIN typically contains alerts, incident reports, and early-warning threat data that helps government agencies and businesses coordinate responses to emerging security threats. The system remains operational for partners while the investigation continues.