Pentagon hit by major cyber breach affecting 3 million military personnel

The United States Department of Defense confirmed a substantial data breach affecting its Defense Manpower Data Center system, compromising sensitive information on millions of military personnel. The unauthorized access to the system occurred over a nine-month period spanning October 2025 through July 2026, according to initial reports of the incident.

The breach exposed records of approximately 2.76 million active military service members and 2.94 million deceased military personnel. The compromised data included both personal identification information and employment-related details, raising significant concerns about the security of military personnel records maintained by the Pentagon.

The Defense Manpower Data Center serves as a centralized repository for military personnel information across the U.S. Armed Forces. The scale of the breach—affecting over 3 million individuals—represents one of the most significant cybersecurity incidents involving defense personnel data in recent years.

Defense officials have not yet disclosed detailed information about the nature of the cyber attack, the methods used by the attackers, or the specific categories of personal information that were accessed. An investigation into the incident is understood to be underway to determine the source and extent of the breach and to implement measures to prevent similar incidents in the future.

The incident underscores ongoing vulnerabilities in critical military information systems and raises questions about cybersecurity protocols protecting sensitive government databases containing information on active and retired service members.