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.

A global cyberattack is unfolding as hackers exploit a critical zero-day vulnerability in Microsoft's SharePoint software, threatening tens of thousands of on-premises servers used by

Microsoft issued an emergency fix to close off a vulnerability in its SharePoint software that hackers have exploited to carry out widespread attacks on businesses and at least some federal agencies.

The newly discovered flaw in Microsoft's SharePoint software has allowed hackers to target dozens of companies and organizations. Only a partial fix has been issued.

More details emerged on the ToolShell zero-day attacks targeting SharePoint servers, but confusion remains over the vulnerabilities.

Microsoft said the company has been "coordinating closely with CISA, DOD Cyber Defense Command, and key cybersecurity partners around the world throughout our response."

Microsoft Corp. advirtió que piratas informáticos están atacando activamente a los clientes de su software de gestión de documentos SharePoint, y los investigadores de seguridad han señalado el riesgo de que se produzcan violaciones de seguridad a gran escala en todo el mundo.