MSRC-CVE-2021-42321 — Microsoft Exchange Server Remote Code Execution Vulnerability

Summary

Impact: Remote Code Execution. Microsoft rating: Important. Exploited according to Microsoft — Exploitation Detected. Customer action: Required.

Details

Where can I find more information about this vulnerability?
Please see Exchange Blog regarding the details of this Exchange release.

According to the CVSS metric, privileges required is low (PR:L). Does the attacker need to be in an authenticated role on the Exchange Server?
Yes, the attacker must be authenticated.

Security updates
15.01.2308.020 — https://support.microsoft.com/help/5007409

Vulnerabilities 1

High 8.8

CVE-2021-42321 Exploited · Ransomware Public exploit EPSS 92%

Microsoft Exchange Server Remote Code Execution Vulnerability

Microsoft Exchange Server Remote Code Execution Vulnerability

Microsoft Microsoft Exchange Server 2019 Cumulative Update 11 Microsoft Exchange Server 2016 Cumulative Update 22 Microsoft Exchange Server 2019 Cumulative Update 10

Nov 10, 2021
KEV Nov 17, 2021

Revision history

2022-06-21 #5
Updated acknowledgment. This is an informational change only.
2021-12-06 #4
Updated acknowledgment. This is an informational change only.
2021-11-17 #3
Removed Exchange Server 2013 from the Security Updates table as it is not affected by this vulnerability.
2021-11-16 #2
Added Microsoft Exchange Server 2013 to the Security Updates table. Customers that are using this version of Microsoft Exchange should install this update to be protected from this vulnerability.
2021-11-09 #1
Information published.

References

CVE-2021-42321 Microsoft Exchange Server Remote Code Execution Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42321
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss