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Critical 1 exploited CVE MSRC-CVE-2021-26857 1 CVE

Microsoft Exchange Server Remote Code Execution Vulnerability

Published Mar 2, 2021 · Updated Mar 16, 2021 · Revision 6

Vendor: Microsoft

Summary

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

Details

Is this vulnerability being used in an active attack?
Yes. The vulnerability described in this CVE is one of four vulnerabilities that are being exploited in an active attack. The security updates address this attack. More information can be found here: https://msrc-blog.microsoft.com/2021/03/02/multiple-security-updates-released-for-exchange-server.
The initial attack in this attack chain targets an Exchange On-prem server that is able to receive untrusted connections from an external source. In addition, the Exchange server would need to be running Microsoft Exchange Server 2013, 2016, or 2019.
Please see On-Premises Exchange Server Vulnerabilities Resource Center – updated March 25, 2021.

If I install the Security Updates for the older Cumulative Updates, am I fully protected from vulnerabilities for all published CVEs?
No, you will be protected from the vulnerabilities documented by CVE-2021-27065, CVE-2021-26855, CVE-2021-26857, CVE-2021-26858. You will not be protected from some previous CVEs as shown in the table below.
Yes: the system is protected from the vulnerability., No: the system is not protected from the vulnerability.
8/14/2018: 8/14/2018, Critical: Critical, CVE-2018-8302: CVE-2018-8302, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, 10/9/2018: 10/9/2018, Important: Important, CVE-2018-8448: CVE-2018-8448, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, 11/13/2018: 11/13/2018, Important: Important, CVE-2018-8581: CVE-2018-8581, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 12/11/2018: 12/11/2018, Important: Important, CVE-2018-8604: CVE-2018-8604, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 1/8/2019: 1/8/2019, Important: Important, CVE-2019-0586: CVE-2019-0586, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 1/8/2019: 1/8/2019, Important: Important, CVE-2019-0588: CVE-2019-0588, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 2/12/2019: 2/12/2019, Important: Important, CVE-2019-0686: CVE-2019-0686, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 2/12/2019: 2/12/2019, Important: Important, CVE-2019-0724: CVE-2019-0724, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 9/10/2019: 9/10/2019, Important: Important, CVE-2019-1233: CVE-2019-1233, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, 10/19/2019: 10/19/2019, Important: Important, CVE-2019-1266: CVE-2019-1266, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, 11/12/2019: 11/12/2019, Critical: Critical, CVE-2019-1373: CVE-2019-1373, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, 2/11/2020: 2/11/2020, Important: Important, CVE-2020-0688: CVE-2020-0688, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, 2/11/2020: 2/11/2020, Important: Important, CVE-2020-0692: CVE-2020-0692, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, 3/10/2020: 3/10/2020, Important: Important, CVE-2020-0903: CVE-2020-0903, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, 9/8/2020: 9/8/2020, Critical: Critical, CVE-2020-16875: CVE-2020-16875, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 10/13/2020: 10/13/2020, Important: Important, CVE-2020-16969: CVE-2020-16969, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 11/10/2020: 11/10/2020, Important: Important, CVE-2020-17083: CVE-2020-17083, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 11/10/2020: 11/10/2020, Important: Important, CVE-2020-17084: CVE-2020-17084, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 11/10/2020: 11/10/2020, Important: Important, CVE-2020-17085: CVE-2020-17085, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Critical: Critical, CVE-2020-17117: CVE-2020-17117, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Critical: Critical, CVE-2020-17132: CVE-2020-17132, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Important: Important, CVE-2020-17141: CVE-2020-17141, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Critical: Critical, CVE-2020-17142: CVE-2020-17142, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Important: Important, CVE-2020-17143: CVE-2020-17143, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Important: Important, CVE-2020-17144: CVE-2020-17144, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 2/9/2021: 2/9/2021, Important: Important, CVE-2021-1730: CVE-2021-1730, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 2/9/2021: 2/9/2021, Important: Important, CVE-2021-24085: CVE-2021-24085, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 3/2/2021: 3/2/2021, Important: Important, CVE-2021-26412: CVE-2021-26412, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 3/2/2021: 3/2/2021, Important: Important, CVE-2021-26854: CVE-2021-26854, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No
3/13/2018: 3/13/2018, Important: Important, CVE-2018-0940: CVE-2018-0940, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, 3/13/2018: 3/13/2018, Important: Important, CVE-2018-0941: CVE-2018-0941, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, 4/3/2018: 4/3/2018, Critical: Critical, CVE-2018-0986: CVE-2018-0986, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 5/8/2018: 5/8/2018, Important: Important, CVE-2018-8151: CVE-2018-8151, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 5/8/2018: 5/8/2018, Important: Important, CVE-2018-8152: CVE-2018-8152, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 5/8/2018: 5/8/2018, Critical: Critical, CVE-2018-8154: CVE-2018-8154, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 5/8/2018: 5/8/2018, Important: Important, CVE-2018-8159: CVE-2018-8159, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, 10/9/2018: 10/9/2018, Important: Important, CVE-2018-8265: CVE-2018-8265, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, 8/14/2018: 8/14/2018, Critical: Critical, CVE-2018-8302: CVE-2018-8302, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, 10/9/2018: 10/9/2018, Important: Important, CVE-2018-8448: CVE-2018-8448, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, 11/13/2018: 11/13/2018, Important: Important, CVE-2018-8581: CVE-2018-8581, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, 12/11/2018: 12/11/2018, Important: Important, CVE-2018-8604: CVE-2018-8604, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, 1/8/2019: 1/8/2019, Important: Important, CVE-2019-0586: CVE-2019-0586, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, 1/8/2019: 1/8/2019, Important: Important, CVE-2019-0588: CVE-2019-0588, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, 2/12/2019: 2/12/2019, Important: Important, CVE-2019-0686: CVE-2019-0686, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, 2/12/2019: 2/12/2019, Important: Important, CVE-2019-0724: CVE-2019-0724, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, 4/9/2019: 4/9/2019, Important: Important, CVE-2019-0817: CVE-2019-0817, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, 4/9/2019: 4/9/2019, Important: Important, CVE-2019-0858: CVE-2019-0858, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, 7/9/2019: 7/9/2019, Important: Important, CVE-2019-1084: CVE-2019-1084, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, 7/9/2019: 7/9/2019, Important: Important, CVE-2019-1136: CVE-2019-1136, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, 7/9/2019: 7/9/2019, Important: Important, CVE-2019-1137: CVE-2019-1137, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, 9/10/2019: 9/10/2019, Important: Important, CVE-2019-1233: CVE-2019-1233, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, 10/19/2019: 10/19/2019, Important: Important, CVE-2019-1266: CVE-2019-1266, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, 11/12/2019: 11/12/2019, Critical: Critical, CVE-2019-1373: CVE-2019-1373, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, 2/11/2020: 2/11/2020, Important: Important, CVE-2020-0688: CVE-2020-0688, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, 2/11/2020: 2/11/2020, Important: Important, CVE-2020-0692: CVE-2020-0692, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, 3/10/2020: 3/10/2020, Important: Important, CVE-2020-0903: CVE-2020-0903, Yes: Yes, Yes: Yes, Yes: Yes, Yes: Yes, No: No, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, 9/8/2020: 9/8/2020, Critical: Critical, CVE-2020-16875: CVE-2020-16875, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 10/13/2020: 10/13/2020, Important: Important, CVE-2020-16969: CVE-2020-16969, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 11/10/2020: 11/10/2020, Important: Important, CVE-2020-17083: CVE-2020-17083, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 11/10/2020: 11/10/2020, Important: Important, CVE-2020-17084: CVE-2020-17084, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 11/10/2020: 11/10/2020, Important: Important, CVE-2020-17085: CVE-2020-17085, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Critical: Critical, CVE-2020-17117: CVE-2020-17117, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Critical: Critical, CVE-2020-17132: CVE-2020-17132, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Important: Important, CVE-2020-17141: CVE-2020-17141, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Critical: Critical, CVE-2020-17142: CVE-2020-17142, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Important: Important, CVE-2020-17143: CVE-2020-17143, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 12/8/2020: 12/8/2020, Important: Important, CVE-2020-17144: CVE-2020-17144, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 2/9/2021: 2/9/2021, Important: Important, CVE-2021-1730: CVE-2021-1730, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 2/9/2021: 2/9/2021, Important: Important, CVE-2021-24085: CVE-2021-24085, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 3/2/2021: 3/2/2021, Important: Important, CVE-2021-26412: CVE-2021-26412, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, 3/2/2021: 3/2/2021, Important: Important, CVE-2021-26854: CVE-2021-26854, Yes: Yes, Yes: Yes, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No, No: No
Microsoft Exchange Server 2013 CU 22 was released February 12, 2019 after which 31 vulnerabilities have been found and remediated., Microsoft Exchange Server 2013 CU 21 was released June 19, 2018 after which 38 vulnerabilities have been found and remediated., Microsoft Exchange Server 2013 Service Pack 1 was released February 25, 2014 after which 82 vulnerabilities have been found and remediated.
Please see Exchange Server build numbers and release dates for more information on Exchange Server Cumulative Updates release dates.

Security updates
15.01.2176.009 — https://support.microsoft.com/help/5000871
14.03.0513.000 — https://support.microsoft.com/help/5000978

Vulnerabilities 1

Revision history

  1. #6

    Microsoft is releasing a security update for CVE-2021-27065, CVE-2021-26855, CVE-2021-26857, and CVE-2021-26858 for Microsoft Exchange Server 2013 Service Pack 1. This update addresses only those CVEs. Customers who want to be protected from these vulnerabilities can apply this update if they are not on a supported cumulative update. Microsoft strongly recommends that customers update to the latest supported cumulative updates.

  2. #5

    Microsoft is releasing the final set of security updates for CVE-2021-27065, CVE-2021-26855, CVE-2021-26857, and CVE-2021-26858 for several Cumulative Updates that are out of support, including Exchange Server 2019, CU1 and CU2; and Exchange Server 2016 CU 8, CU 9, CU10, and CU11. These updates address only those CVEs. Customers who want to be protected from these vulnerabilities can apply these updates if they are not Exchange Server on a supported cumulative update. Microsoft strongly recommends that customers update to the latest supported cumulative updates.

  3. #4

    Microsoft is releasing security updates for CVE-2021-27065, CVE-2021-26855, CVE-2021-26857, and CVE-2021-26858 for several Cumulative Updates that are out of support, including Exchange Server 2019 CU 3; and Exchange Server 2016 CU 17, CU 13, CU12; and Exchange Server 2013 CU 22, CU 21. These updates address only those CVEs. Customers who want to be protected from these vulnerabilities can apply these updates if they are not on a supported cumulative update. Microsoft strongly recommends that customers update to the latest supported cumulative updates.

  4. #3

    Microsoft is releasing security updates for CVE-2021-27065, CVE-2021-26855, CVE-2021-26857, and CVE-2021-26858 for several Cumulative Updates that are out of support, including Exchange Server 2019 CU 6, CU 5, and CU 4 and Exchange Server 2016 CU 16, CU 15, and CU14. These updates address only those CVEs. Customers who want to be protected from these vulnerabilities can apply these updates if they are not on a supported cumulative update. Microsoft strongly recommends that customers update to the latest supported cumulative updates.

  5. #1

    Information published.

  6. #2

    Updated one or more CVSS scores for the affected products. This is an informational change only.

References