Pentagon data breach exposes 2.7 million military personnel records

A significant data breach at the Defense Manpower Data Center (DMDC) has exposed the personal information of approximately 2.76 million living U.S. military and civilian personnel. The breach also affected roughly 294,000 deceased individuals.

Unauthorized users accessed unencrypted files through a file-sharing vulnerability between October 2025 and July 2026. The compromised data includes Social Security numbers, dates of birth, demographic information, employment details, and military service records. The DMDC is a critical Department of Defense unit responsible for maintaining over 60 million records used to manage benefits, entitlements, and identity management for service members, employees, and contractors.

The vulnerability was discovered in July, though those impacted were not notified until September 18. While the Department of Defense stated it has found no evidence that the exposed information has been misused, the identities of the attackers remain unknown.