Microsoft Security Response Center yesterday released several security updates for Microsoft Exchange Server. These updates were targeted at addressing vulnerabilities that have been used in a few focused and targeted attacks. The vulnerabilities have been deemed to be very critical in nature and Microsoft urges and advises its customers to update the affected systems without further delay to protect themselves against these attacks. Microsoft has asked its users to prioritize updating external-facing Exchange Servers and then moving on to update others. Microsoft Threat Intelligence Center (MSTIC) attributes this campaign with high confidence to HAFNIUM.”]
Source: https://gbhackers.com/microsoft-issues-emergency-patch/

