New estimates regarding the recently-exploited Microsoft SharePoint vulnerabilities now evaluate that as many as 400 organizations may have been targeted.

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.

Unknown threat actors have breached the National Nuclear Security Administration's network in attacks exploiting a recently patched Microsoft SharePoint zero-day vulnerability chain.