CVE-2021-34473

Microsoft Exchange Server Remote Code Execution Vulnerability

CVE-2021-34473 is fixed in 5 products on 1 platform, first by KB5001779, released April 13, 2021. It is being exploited: CISA added it to the Known Exploited Vulnerabilities catalog on November 3, 2021, with known ransomware use. Patch Radar priority: Patch now.

Patch nowCISA KEVKnown ransomware usePublicly disclosed

CVSS

9.1

Critical

Exploitation

Exploited

Listed by CISA

CISA KEV

Nov 3, 2021

Federal due date Nov 17, 2021. Known ransomware use

EPSS

1.0000

99th percentile

Where it's fixed

Product	Fix	Released
Microsoft
Microsoft Exchange Server 2013 Cumulative Update 23	KB5001779	Apr 13, 2021
Microsoft Exchange Server 2016 Cumulative Update 19	KB5001779	Apr 13, 2021
Microsoft Exchange Server 2016 Cumulative Update 20	KB5001779	Apr 13, 2021
Microsoft Exchange Server 2019 Cumulative Update 8	KB5001779	Apr 13, 2021
Microsoft Exchange Server 2019 Cumulative Update 9	KB5001779	Apr 13, 2021

Details

Published
July 13, 2021
CISA required action
Apply updates per vendor instructions.
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34473

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