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CVE-2021-42321

Microsoft Exchange Server Remote Code Execution Vulnerability

Basic Information

CVE State
PUBLISHED
Reserved Date
October 12, 2021
Published Date
November 10, 2021
Last Updated
February 04, 2025
Vendor
Microsoft
Product
Microsoft Exchange Server 2016 Cumulative Update 21, Microsoft Exchange Server 2019 Cumulative Update 10, Microsoft Exchange Server 2016 Cumulative Update 22, Microsoft Exchange Server 2019 Cumulative Update 11
Description
Microsoft Exchange Server Remote Code Execution Vulnerability

CVSS Scores

CVSS v3.1

8.8 - HIGH

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

SSVC Information

Exploitation
active
Technical Impact
total

Exploit Status

Exploited in the Wild
Yes (added 2021-11-17 00:00:00 UTC) Source
Proof of Concept Available
Yes (added 2022-10-08 13:00:23 UTC) Source
Used in Malware
Yes (added 2021-11-17 00:00:00 UTC) Source

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42321 http://packetstormsecurity.com/files/166153/Microsoft-Exchange-Server-Remote-Code-Execution.html http://packetstormsecurity.com/files/168131/Microsoft-Exchange-Server-ChainedSerializationBinder-Remote-Code-Execution.html

Known Exploited Vulnerability Information

Source Added Date
CISA 2021-11-17 00:00:00 UTC

Scanner Integrations

Scanner URL Date Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/http/exchange_chainedserializationbinder_rce.rb 2025-04-29 11:01:37 UTC

Potential Proof of Concepts

Warning: These PoCs have not been tested and could contain malware. Use at your own risk.

7BitsTeam/exch_CVE-2021-42321

Type: github • Created: 2022-10-08 13:00:23 UTC • Stars: 10

DarkSprings/CVE-2021-42321

Type: github • Created: 2021-11-23 02:26:26 UTC • Stars: 85

Microsoft Exchange Server Poc