Microsoft blamed two Chinese nation-state actors for exploiting recently discovered security flaws in SharePoint to infiltrate vulnerable organizations, like schools, state governments, and the U.S. government’s top nuclear security agency.

Microsoft warned of "active attacks" targeting some users of its SharePoint software over the weekend and released an emergency patch that fixes only some versions of the vulnerable server software. Why it matters: It remains unclear how many businesses were already hacked prior to Microsoft's warning,