The Pentagon has suffered a major cybersecurity breach that exposed personal information of nearly 3 million living people, including US military personnel, civilian employees, contractors and veterans.
According to ABC News, a US defence official confirmed that the Defense Manpower Data Center (DMDC) information system was accessed without authorisation between October 2025 and July 2026.
The official said the system “experienced unauthorized access of personally identifiable information by a small number of unauthorized users between October 2025 and July 2026.”
The DMDC serves as one of the Pentagon’s main repositories of personnel records. Its databases contain information on active-duty and reserve military personnel, civilian employees, contractors and military veterans.
The breach affected about 2.76 million living people and around 294,000 deceased individuals, according to the report.
Defence officials said the DMDC immediately addressed the vulnerability after discovering the unauthorised access. The compromised information included Social Security numbers and details about military and civilian job positions.
Officials said they had so far found no evidence that the exposed information had been misused.
The breach could have affected a much larger number of people. The DMDC reportedly holds records on more than 60 million individuals, meaning the nearly three million affected records represent about one in 20 of the people whose information it stores.
CNN reported that the accessed information also included the “occupational specialty” of military service members. Combined with Social Security numbers, such information could potentially help foreign adversaries gain a clearer picture of the roles, deployment and purposes of US personnel operating around the world.
The stolen information was reportedly not encrypted, making it relatively easy to cross-reference with data from other breaches or leaks.
No hacking group has publicly claimed responsibility for the Pentagon breach so far.
The incident comes after the recent reported breach involving FBI employee data, raising concerns over the security of sensitive US government information.
The two incidents have highlighted the potential scale of cyber threats targeting major US government databases and could signal a growing challenge for agencies responsible for protecting sensitive personnel information.
