U.S. Nuclear Agency Hit in Microsoft SharePoint Hack, No Sensitive Data Breached

The U.S. National Nuclear Security Administration (NNSA), the agency responsible for maintaining America’s nuclear weapons arsenal, was reportedly affected by a cyberattack targeting Microsoft’s (NASDAQ: MSFT) SharePoint software, Bloomberg reported Tuesday, citing a source familiar with the matter.

While the breach raises national security concerns due to NNSA's role, no classified or sensitive data is believed to have been compromised. The incident is part of a broader cyber intrusion involving vulnerabilities in Microsoft's SharePoint, a popular document management platform used across U.S. government agencies.

The report follows increasing scrutiny of Microsoft's cybersecurity protocols after several high-profile breaches in recent years. The latest hack underscores growing risks tied to third-party software used in critical federal infrastructure.

Microsoft, the U.S. Department of Energy, and the Cybersecurity and Infrastructure Security Agency (CISA) have not yet responded to media inquiries about the incident. Reuters noted it could not independently verify the Bloomberg report.

Security analysts warn that even without classified data exposure, breaches into agencies like the NNSA can reveal internal systems and workflows, which may be valuable to foreign threat actors.

This incident adds to pressure on Microsoft as federal agencies and private-sector partners demand more robust security features across its cloud and collaboration tools. As SharePoint remains widely deployed across government systems, the breach is likely to reignite debate over secure digital infrastructure and reliance on centralized platforms.

The NNSA cyberattack highlights ongoing vulnerabilities in national cybersecurity posture, emphasizing the importance of proactive defense and regular auditing of software dependencies in high-stakes government environments.