The Pentagon has acknowledged a data breach of the Defense Manpower Data Centre (DMDC) information system. Personal data of more than 3 million individuals were exposed. The incident affected 2.76 million persons and 294,000 expired people.

As per reports unauthorized users accessed the DMDC system between October 2025 and July 2026. The intrusion exploited a vulnerability in a file-sharing system that allowed access to files on an affected server. DMDC found the weakness on July 16.  It is not clear which files were accessed and the identity of the party behind the incident.

The persons whose personal information were accessed were informed via mail. The length of the data breach and the quantity of personal details were exposed is a security risk. The accessed files had unencrypted data. The exposed details may include names, dates of birth, Social Security numbers and others.

Impacted persons are being given 1 year of free credit monitoring and identity restoration services. This breach highlights the need for the Pentagon to encrypt stored data and continuously monitor file access. Efforts are ongoing to find the identity of the party who accessed the files and the motive behind the data breach.

SOURCES:-

https://cybersecuritynews.com/pentagon-data-breach/

https://time.com/article/2026/09/29/pentagon-department-defense-manpower-data-center-breach-personnel-information/

https://gbhackers.com/pentagon-data-breach-exposes-3-million-people/

https://saharareporters.com/2026/09/29/hackers-breach-us-pentagon-database-expose-information-over-3million-personnel