Hackers stole millions of US military personnel records during months-long data breach
A data breach at the U.S. Defense Manpower Data Center exposed the unencrypted personal information of approximately 3.1 million current and former military personnel. The breach occurred between late 2025 and mid-2026, compromising sensitive data including Social Security numbers.
Why it matters
This massive breach of government data poses significant national security risks and highlights vulnerabilities in federal cybersecurity infrastructure.
The U.S. government is reportedly alerting millions of current and former U.S. military service members and staff that their personal information was stolen during a months-long breach of the Pentagon’s personnel records, the latest in a spate of thefts involving federal workers’ data in recent months.
A data breach notification from the Defense Manpower Data Center (DMDC) shared on Reddit says that several unauthorized users exploited a security vulnerability in an unspecified file-sharing system over several months between October 2025 and mid-July 2026.
The breach exposed personally identifiable information, including Social Security numbers, alongside a person’s name, date of birth, sex, race, and other information about their military service. The notice says that the personnel records were unencrypted.
According to CNN and Federal News Network , a Pentagon official said the breach affects about 2.8 million living people, and close to 300,000 people who are deceased.
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