# Pentagon military personnel data breach

> Live situation record from CLSTR: https://clstr.news/situations/pentagon-military-personnel-data-breach
> Updated: 2026-09-28T19:26:51.000Z. Sources: 21. Developments: 2.

A data breach within the Pentagon’s human resources system has exposed the personal information of millions of current and former military personnel. Unauthorized users accessed a vulnerable server belonging to the Defense Manpower Data Center (DMDC) starting in October 2025, with the breach remaining undetected until July 2026.

Subsequent confirmation from the Pentagon specified that the breach affects 2.76 million ‘living individuals’ and 294,000 ‘deceased individuals.’ The compromised group includes military personnel, civilian employees, contractors, and their families. Exposed data includes unencrypted Social Security numbers, names, dates of birth, contact information, and occupational specialties.

While the Pentagon stated there are currently ‘no indications of misuse’ of the data, national security experts warn that the information—particularly the combination of Social Security numbers and occupational specialties—could be used by foreign intelligence services to track personnel or by cybercriminals for extortion. The DMDC, which manages over 60 million personnel records, remediated the vulnerability immediately upon discovery. The identity of the attackers remains unknown.

In response to the incident, the Department of Defense is offering identity protection and credit monitoring services to those affected. The breach continues to raise significant national security and counterintelligence concerns regarding the vulnerability of military human resources infrastructure.

## Claims

- A Defense Manpower Data Center (DMDC) information system experienced unauthorized access of personally identifiable information. (corroborated by 6 sources)
- The breach affected 2.76 million living individuals and 294,000 deceased individuals. (corroborated by 6 sources)
- Unauthorized access occurred between October 2025 and July 2026. (corroborated by 6 sources)
- Exposed data included Social Security numbers and occupational specialties. (corroborated by 6 sources)
- There is currently no evidence that the breached data has been misused. (corroborated by 6 sources)
- The DMDC maintains more than 60 million personnel records. (corroborated by 5 sources)

## Timeline

### 2026-09-28: Pentagon data breach exposes sensitive info of 3 million people

A Pentagon data breach has exposed the Social Security numbers and job details of nearly 3 million military and civilian personnel, raising significant national security concerns.

9 sources. https://clstr.news/cluster/pentagon-data-breach-exposes-personal-info-of-millions-of-military-personnel

### 2026-09-25: Pentagon data breach exposes personal information of millions of military personnel

A Pentagon data breach at the Defense Manpower Data Center has exposed the unencrypted personal data of up to four million military personnel, raising significant national security concerns.

14 sources. https://clstr.news/cluster/pentagon-data-breach-exposes-military-personnel-information

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Cite as: Pentagon military personnel data breach. CLSTR, https://clstr.news/situations/pentagon-military-personnel-data-breach