NEW YORK (AP) — Microsoft has issued an emergency fix to close off a vulnerability in Microsoft’s SharePoint software that hackers have exploited to carry out widespread attacks on businesses and at least some federal agencies.

Hackers in recent weeks have exploited flaws in SharePoint, a document management system developed by Microsoft Corp., to try to steal sensitive data from hundreds of victims.

Microsoft has issued a high-priority security alert over ongoing cyberattacks targeting its SharePoint server software. The company urged affected users to apply critical security updates