Pentagon Data Breach Exposed Information On Nearly 3 Million People

A breach of the Pentagon’s sprawling personnel database exposed sensitive information belonging to nearly 3 million people, including Social Security numbers and details about the jobs they held, according to a US defense official, Luis Martinez and Luke Barr reported for ABC News.

The Pentagon in Washington, D.C. A breach of a Defense Manpower Data Center system exposed sensitive personnel information. [Photo: USGS]

The breach affected 2.76 million living people and another 294,000 who are deceased, the official said.

The scope and sensitivity of the exposed information could raise national security concerns, particularly because the files included details about the jobs performed by military and civilian personnel.

“A Defense Manpower Data Center (DMDC) information system experienced unauthorized access of personally identifiable information by a small number of unauthorized users between October 2025 and July 2026.

Upon discovery, DMDC immediately remediated the vulnerability,” the official said.

The Defense Manpower Data Center serves as one of the Pentagon’s main repositories for personnel records, holding information on active-duty and reserve troops, civilian employees, contractors, retirees, veterans and military family members.

The agency maintains more than 60 million personnel records. Military Times first reported the breach.

The unauthorized access continued from October 2025 until July 2026, when DMDC discovered and patched the vulnerability. The defense official said there was no evidence that the exposed information had been misused.