KLA12342
Multiple vulnerabilities in Microsoft Exchange Server

Multiple vulnerabilities were found in Microsoft Exchange Server. Malicious users can exploit these vulnerabilities to perform cross-site scripting attack, execute arbitrary code, spoof user interface.

Below is a complete list of vulnerabilities:

1. A spoofing vulnerability in Microsoft Exchange Server can be exploited remotely to spoof user interface.
2. A remote code execution vulnerability in Microsoft Exchange Server can be exploited remotely to execute arbitrary code.

The following public exploits exists for this vulnerability:

https://github.com/timb-machine-mirrors/testanull-CVE-2021-42321_poc.py

Malware exists for this vulnerability. Usually such malware is classified as Exploit. More details.

Microsoft Exchange Server 2019 Cumulative Update 10
Microsoft Exchange Server 2019 Cumulative Update 11
Microsoft Exchange Server 2013 Cumulative Update 23
Microsoft Exchange Server 2016 Cumulative Update 22
Microsoft Exchange Server 2016 Cumulative Update 21

Install necessary updates from the KB section, that are listed in your Windows Update (Windows Update usually can be accessed from the Control Panel)

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