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

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

The Department of Energy, which oversees the agency that manages the US nuclear weapons stockpile, confirms it was affected by the SharePoint bug, but says it was 'minimally impacted.'