Pentagon Data Breach Exposes Millions of Sensitive Records According to a recent report by TomsHardware, the Defense Manpower Data Center (DMDC) of the United States Department of Defense suffered a massive unauthorized infiltration spanning from October 2025 through July 2026. Scope of the DMDC Cyberattack Department of Defense officials disclosed that this catastrophic event compromised the sensitive records of 2.76 million living individuals and 294,000 deceased personnel.