The Department of Homeland Security is looking into a compromise of its system, utilized by federal, state, and local governments as well as law enforcement for intelligence sharing, with one senior politician cautioning that the data leak could pose a threat to national security.

News platforms Nextgov, which first reported the story, and Bleeping Computer indicate that DHS officials are investigating a cyber intrusion on its Homeland Security Information Network, or HSIN, which facilitates the planning, coordination, and information exchange among government entities and local officials regarding significant incidents and emergency responses.

The cybercriminals reportedly accessed HSIN servers in late May and early June, possibly compromising information exchanged via the platform, according to Nextgov.

In response to an email inquiry, a spokesperson for DHS, who wished to remain unnamed, indicated that the department is “aware of a recent cyber incident involving a specific, unclassified legacy information sharing environment.”

“We promptly took steps to isolate the impacted systems, alleviate the vulnerability, and initiate a thorough forensic inquiry,” the statement read. The investigation is still underway, and the spokesperson refrained from providing additional comments.

It remains unclear what specific data was compromised or the volume of information taken, and Homeland Security did not respond to TechCrunch’s inquiries regarding the incident. A previously reported security oversight in 2023 had indicated that HSIN held personal data shared among law enforcement in connection with the surveillance of American citizens.

The occurrence involving HSIN brings renewed examination of the government’s capability to secure its own cybersecurity, following over a year of significant budget cuts throughout the federal government, including the Department of Homeland Security and its cybersecurity arm CISA, during the Trump administration.

Although the information shared through HSIN is unclassified, the details “are highly sensitive, and their disclosure poses risks to national security,” stated Mark Warner, a Democratic senator from Virginia and the ranking member of the Senate Intelligence Committee, in a statement. 

Warner remarked that the HSIN platform is being utilized to support the World Cup games currently taking place in the United States, and was also used last year to coordinate the response to a mid-air collision between an American Airlines aircraft and a U.S. Army Black Hawk helicopter over Washington, D.C., resulting in 67 fatalities.

The identities, affiliations, and intentions of the hackers who infiltrated HSIN are unknown, but the breach represents the latest in a series of security failures impacting the federal government over the past year. 

Since the Trump administration took office in January 2025, the federal government has encountered numerous significant cybersecurity breaches, including the disclosure of classified information and military strategies via apps like Signal that are not authorized for governmental use, the unauthorized access of federal databases containing Americans’ personal data by members of Elon Musk’s Department of Government Efficiency, or DOGE, and a reported public leak of extensive passwords and credentials by a CISA contractor that granted access to government cloud systems.

Earlier this year, the FBI informed lawmakers in Congress that it had to announce a “major cyber incident” after revealing the phone numbers of individuals under surveillance by federal agents, potentially giving those targets a strategic advantage.

Do you have more information regarding the DHS HSIN cyberattack? We would love to hear from you. To reach out to Zack Whittaker securely, connect via Signal username zackwhittaker.1337 or by email: [email protected].

Updated with a comment from Homeland Security.