The US agency responsible for maintaining and designing the nation’s cache of nuclear weapons was among those breached by a hack of Microsoft Corp.’s SharePoint document management software, according to a person with knowledge of the matter.

Hackers are exploiting a flaw in a commonly used Microsoft program to gain access to passwords, sensitive data and more.

Last year, the Department of Homeland Security released a scathing report detailing Microsoft’s mistakes during a 2023 hack in which China stole thousands of emails from top government officials. Two years before that, China-linked cyberattackers compromised more than 250,000 Microsoft Exchange servers.

Hackers have breached about 400 government agencies, corporations and other groups, according to estimates from Eye Security.

A critical flaw in a major Microsoft document storage tool is hitting the organizations least able to defend themselves, security researchers and incident responders tell Axios. Why it matters: Schools,

A significant flaw in a widely used Microsoft product allowed multiple Chinese-linked hacking groups to breach dozens of organizations across the globe and at least two U.S. federal agencies.