The incident has reportedly impacted the servers of federal agencies, schools, and energy companies. Some emergency patches have been deployed. On July 19, Microsoft alerted users that it was experiencing an active cyberattack on its SharePoint servers,

The zero-day vulnerability — which was first disclosed late Saturday — has been exploited by several Chinese state-aligned groups, according to Microsoft.

Multiple hacking groups—including state actors from China—have targeted a vulnerability in older, on-premises versions of the file-sharing tool after a flawed attempt to patch it.