CVE-2021-27065: Microsoft Exchange Server Remote Code Execution Vulnerability
Published Mar 2, 2021
·Updated
Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution. This vulnerability is part of the ProxyLogon exploit chain.
Other sources
Microsoft Exchange Server Remote Code Execution Vulnerability
— NVD
Affected Software
26 affected components
Microsoft Exchange Server
Microsoft Exchange Server=2013-cumulative_update_22
Microsoft Exchange Server=2013-cumulative_update_23
Microsoft Exchange Server=2013-sp1
Microsoft Exchange Server=2016-cumulative_update_10
Microsoft Exchange Server=2016-cumulative_update_11
Microsoft Exchange Server=2016-cumulative_update_12
Microsoft Exchange Server=2016-cumulative_update_13
Microsoft Exchange Server=2016-cumulative_update_14
Microsoft Exchange Server=2016-cumulative_update_15
Microsoft Exchange Server=2016-cumulative_update_16
Microsoft Exchange Server=2016-cumulative_update_17
Microsoft Exchange Server=2016-cumulative_update_18
Microsoft Exchange Server=2016-cumulative_update_19
Microsoft Exchange Server=2016-cumulative_update_8
Microsoft Exchange Server=2016-cumulative_update_9
Microsoft Exchange Server=2019
Microsoft Exchange Server=2019-cumulative_update_1
Microsoft Exchange Server=2019-cumulative_update_2
Microsoft Exchange Server=2019-cumulative_update_4
Microsoft Exchange Server=2019-cumulative_update_5
Microsoft Exchange Server=2019-cumulative_update_6
Microsoft Exchange Server=2019-cumulative_update_7
Microsoft Exchange Server=2019-cumulative_update_8
Microsoft Exchange Server=2013-cumulative_update_21
Microsoft Exchange Server=2019-cumulative_update_3
Remediation
Event History
Mar 2, 2021
CVE Published
via MITRE·11:55 PM
Data Sourced
via MITRE·11:55 PM
DescriptionSeverity
Mar 3, 2021
Data Sourced
via NVD·12:15 AM
RemedyDescriptionSeverityWeaknessAffected Software
Nov 3, 2021
Known Exploited
via CISA·12:00 AM
Known Ransomware
via CISA·12:00 AM
Dec 2, 2023
News Published
06:54 PM
Oct 7, 2024
News Published
via BleepingComputer·02:51 PM
News Published
via BleepingComputer·02:52 PM
Nov 27, 2024
News Published
via The Register·11:44 PM
News Published
via The Register·11:48 PM
May 2, 2025
News Published
via BleepingComputer·02:32 PM
Apr 30, 2026
News Published
via The Register·11:00 AM
Peer vulnerabilities
Found alongside the following vulnerabilities.
Frequently Asked Questions
1
What is CVE-2021-27065?
CVE-2021-27065 is a remote code execution vulnerability in Microsoft Exchange Server.
2
How does CVE-2021-27065 impact Microsoft Exchange Server?
CVE-2021-27065 allows an attacker to remotely execute code on a vulnerable Microsoft Exchange Server.
3
What is the severity of CVE-2021-27065?
CVE-2021-27065 has a severity rating of 7.8 (high).
4
Which versions of Microsoft Exchange Server are affected by CVE-2021-27065?
CVE-2021-27065 affects Microsoft Exchange Server 2013, 2016, and 2019.
5
How can I mitigate CVE-2021-27065?
To mitigate CVE-2021-27065, apply the security updates provided by Microsoft and follow the recommended mitigation measures.