CVE-2021-26412
published 2021-03-03CVE-2021-26412: Microsoft Exchange Server Remote Code Execution Vulnerability
PriorityP261high7.2CVSS 3.1
AVNACLPRHUINSUCHIHAH
EXPLOIT
EPSS
32.98%
98.2th percentile
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected
34 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | exchange_server | — | — |
| microsoft | exchange_server | — | — |
| microsoft | exchange_server | — | — |
| microsoft | exchange_server | — | — |
| microsoft | exchange_server | — | — |
| microsoft | microsoft_exchange_server_2013_cumulative_update_23 | >= 15.00.0 < 15.00.1497.012 | 15.00.1497.012 |
| microsoft | microsoft_exchange_server_2016_cumulative_update_18 | >= 15.01.0 < 15.01.2106.013 | 15.01.2106.013 |
| microsoft | microsoft_exchange_server_2016_cumulative_update_19 | >= 15.01.0 < 15.01.2176.009 | 15.01.2176.009 |
| microsoft | microsoft_exchange_server_2019_cumulative_update_7 | >= 15.02.0 < 15.02.0721.013 | 15.02.0721.013 |
| microsoft | microsoft_exchange_server_2019_cumulative_update_8 | >= 15.02.0 < 15.02.0792.010 | 15.02.0792.010 |
| msrc | microsoft_exchange_server_2010_service_pack_3 | — | — |
| msrc | microsoft_exchange_server_2013_cumulative_update_21 | — | — |
| msrc | microsoft_exchange_server_2013_cumulative_update_22 | — | — |
| msrc | microsoft_exchange_server_2013_cumulative_update_23 | — | — |
| msrc | microsoft_exchange_server_2013_service_pack_1 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_10 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_11 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_12 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_13 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_14 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_15 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_16 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_17 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_18 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_19 | — | — |
Detection & IOCsextracted from sources · hover to see the quote
- ·Exploit Status: Not publicly disclosed and not exploited in the wild at time of publication. Microsoft rates exploitation as 'Less Likely' for both latest and older software releases. ↗
- ·Affected product is Microsoft Exchange Server. Patches are available via the referenced Microsoft download links and KB5000871. ↗
CVSS provenance
nvdv3.17.2HIGHCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
nvdv2.06.5MEDIUMAV:N/AC:L/Au:S/C:P/I:P/A:P
vendor_msrc9.1CRITICAL
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Microsoft
Microsoft Exchange Server Remote Code Execution Vulnerability
vendor_msrc·2021-03-09·CVSS 9.1
CVE-2021-26412 [CRITICAL] Microsoft Exchange Server Remote Code Execution Vulnerability
Microsoft Exchange Server Remote Code Execution Vulnerability
Microsoft Exchange Server: Microsoft Exchange Server
Microsoft: Microsoft
Impact: Remote Code Execution
Exploit Status: Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation Less Likely;Older Software Release:Exploitation Less Likely;DOS:N/A
Reference: http://www.microsoft.com/download/details.aspx?familyid=1255ecd7-b187-4839-96c9-1fc5e05df7b6
Reference: https://support.microsoft.com/help/5000871
Reference: http://www.microsoft.com/download/details.aspx?familyid=2aadda14-b8aa-4370-a492-0a6818facce8
Reference: http://www.microsoft.com/download/details.aspx?familyid=192fa60f-664a-4f3e-b19f-e295135e469b
Reference: http://www.microsoft.com/download/details.aspx?familyid=31211a48-0cef-462e-bb11-c36440f80bb3
Microsoft
Microsoft Exchange Server Remote Code Execution Vulnerability
vendor_msrc·2021-03-09·CVSS 7.8
CVE-2021-26857 [CRITICAL] Microsoft Exchange Server Remote Code Execution Vulnerability
Microsoft Exchange Server Remote Code Execution Vulnerability
FAQ: 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.
What is the target for this attack?
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.
Where can I get more information about how to protect myself from the vulnerabilities?
Pleas
Microsoft
Microsoft Exchange Server Remote Code Execution Vulnerability
vendor_msrc·2021-03-09·CVSS 9.1
CVE-2021-26855 [CRITICAL] Microsoft Exchange Server Remote Code Execution Vulnerability
Microsoft Exchange Server Remote Code Execution Vulnerability
FAQ: 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.
What is the target for this attack?
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.
Where can I get more information about how to protect myself from the vulnerabilities?
Pleas
Microsoft
Microsoft Exchange Server Remote Code Execution Vulnerability
vendor_msrc·2021-03-09·CVSS 7.8
CVE-2021-27065 [CRITICAL] Microsoft Exchange Server Remote Code Execution Vulnerability
Microsoft Exchange Server Remote Code Execution Vulnerability
FAQ: 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.
What is the target for this attack?
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.
Where can I get more information about how to protect myself from the vulnerabilities?
Pleas
Microsoft
Microsoft Exchange Server Remote Code Execution Vulnerability
vendor_msrc·2021-03-09·CVSS 7.8
CVE-2021-26858 [CRITICAL] Microsoft Exchange Server Remote Code Execution Vulnerability
Microsoft Exchange Server Remote Code Execution Vulnerability
FAQ: 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.
What is the target for this attack?
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.
Where can I get more information about how to protect myself from the vulnerabilities?
Pleas
GHSA
GHSA-rwm8-8c4x-v87q: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-2685
ghsa_unreviewed·2022-05-24·CVSS 9.1
CVE-2021-27065 [CRITICAL] CWE-22 GHSA-rwm8-8c4x-v87q: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-2685
Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27078.
GHSA
GHSA-6784-2mh5-cq56: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26857, CVE-2021-2685
ghsa_unreviewed·2022-05-24·CVSS 9.1
CVE-2021-26855 [CRITICAL] CWE-918 GHSA-6784-2mh5-cq56: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26857, CVE-2021-2685
Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065, CVE-2021-27078.
GHSA
GHSA-2xf7-r7hp-r5qc: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26855, CVE-2021-26857, CVE-2021-2685
ghsa_unreviewed·2022-05-24·CVSS 9.1
CVE-2021-26854 [CRITICAL] GHSA-2xf7-r7hp-r5qc: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26855, CVE-2021-26857, CVE-2021-2685
Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065, CVE-2021-27078.
GHSA
GHSA-r4wp-245q-vr5w: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-2685
ghsa_unreviewed·2022-05-24·CVSS 9.1
CVE-2021-26858 [CRITICAL] GHSA-r4wp-245q-vr5w: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-2685
Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-26857, CVE-2021-27065, CVE-2021-27078.
GHSA
Rails is bad
ghsa_unreviewed·2022-05-24·CVSS 9.1
CVE-2021-26857 [CRITICAL] CWE-502 Rails is bad
Rails is bad
Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-26858, CVE-2021-27065, CVE-2021-27078.
GHSA
GHSA-xc64-jf3q-gg7j: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26854, CVE-2021-26855, CVE-2021-26857, CVE-2021-2685
ghsa_unreviewed·2022-05-24·CVSS 6.6
CVE-2021-26412 [MEDIUM] GHSA-xc64-jf3q-gg7j: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26854, CVE-2021-26855, CVE-2021-26857, CVE-2021-2685
Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26854, CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065, CVE-2021-27078.
GHSA
GHSA-5rg7-hgww-7chr: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-2685
ghsa_unreviewed·2022-05-24·CVSS 9.1
CVE-2021-27078 [CRITICAL] GHSA-5rg7-hgww-7chr: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-2685
Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065.
No detection rules found.
Nuclei
Microsoft Exchange Server SSRF Vulnerability
nuclei·CVSS 7.2
CVE-2021-26855 [HIGH] Microsoft Exchange Server SSRF Vulnerability
Microsoft Exchange Server SSRF Vulnerability
This vulnerability is part of an attack chain that could allow remote code execution on Microsoft Exchange Server. The initial attack requires the ability to make an untrusted connection to Exchange server port 443. Other portions of the chain can be triggered if an attacker already has access or can convince an administrator to open a malicious file. Be aware his CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065, and CVE-2021-27078.
Template:
id: CVE-2021-26855
info:
name: Microsoft Exchange Server SSRF Vulnerability
author: madrobot
severity: critical
description: This vulnerability is part of an attack chain that could allow remote code execution on Microsoft Exchange Server. The initial
Trendmicro
March Patch Tuesday: Fixes for Exchange Server, IE
blogs_trendmicro·2021-03-10·CVSS 9.1
[CRITICAL] March Patch Tuesday: Fixes for Exchange Server, IE
# March Patch Tuesday: Fixes for Exchange Server, IE
This month’s Patch Tuesday includes fixes already released for the Microsoft Exchange Server zero-day flaws attributed to Hafnium attacks.
By: Trend Micro
2021/03/10
Read time: ( words)
Save to Folio
This month’s Patch Tuesday features close to a hundred fixes, almost doubling last month’s total. The list includes patches already released for the Microsoft Exchange Server zero-day flaws attributed to Hafnium attacks.
Out of 89 patches released, 14 were rated Critical while the rest were deemed Important. Most of the critical vulnerabilities involve remote code execution (RCE) link except for an information disclosure bug. Fifteen of these were reported by the Zero Day Initiative (ZDI).
Microsoft Exchange Server Vulnerabilities
Th
Sentinelone
SentinelOne and HAFNIUM / Microsoft Exchange 0-days
blogs_sentinelone·2021-03-04
SentinelOne and HAFNIUM / Microsoft Exchange 0-days
On Tuesday, March 2nd, Microsoft released an out-of-band security update addressing a total of 7 CVEs, four of which are associated with ongoing, targeted attacks. The update was in response to an active campaign that was seen on Microsoft clients compromising Exchange servers by bypassing authentication and allowing attackers to read emails and potentially penetrate enterprise networks without the need to authenticate.
The SentinelLabs team has been closely tracking HAFNIUM and Exchange Server impacts. Customers with the Deep Visibility threat hunting module (STAR) may also automate responses (alerts, network quarantine, kill, quarantine) should these IoCs be seen in the future. Our customers can stay ahead of this emerging threat with our protection capabilities and real-time alerts.
#
Talos
Threat Advisory: HAFNIUM and Microsoft Exchange zero-day
blogs_talos·2021-03-04·CVSS 9.1
CVE-2021-26855 [CRITICAL] Threat Advisory: HAFNIUM and Microsoft Exchange zero-day
Microsoft released patches for four vulnerabilities in Exchange Server on March 2, disclosing that these vulnerabilities were being exploited by a previously unknown threat actor, referred to as HAFNIUM.
The vulnerabilities in question — CVE-2021-26855, CVE-2021-26857, CVE-2021-26858 and CVE-2021-27065 — affect Microsoft Exchange Server 2019, 2016, 2013 and the out-of-support Microsoft Exchange Server 2010. The patches for these vulnerabilities should be applied as soon as possible. Microsoft Exchange Online is not affected.
Patches for an additional three vulnerabilities in the same software have also been released: CVE-2021-26412, CVE-2021-26854 and CVE-2021-27078. It is believed that these vulnerabilities have not yet been exploited in the wild.
## Threat activity details
The threat
Talos
Threat Advisory: HAFNIUM and Microsoft Exchange zero-day
blogs_talos·2021-03-04·CVSS 9.1
CVE-2021-26855 [CRITICAL] Threat Advisory: HAFNIUM and Microsoft Exchange zero-day
## Threat Advisory: HAFNIUM and Microsoft Exchange zero-day
Microsoft released patches for four vulnerabilities in Exchange Server on March 2, disclosing that these vulnerabilities were being exploited by a previously unknown threat actor, referred to as HAFNIUM .
The vulnerabilities in question — CVE-2021-26855 , CVE-2021-26857 , CVE-2021-26858 and CVE-2021-27065 — affect Microsoft Exchange Server 2019, 2016, 2013 and the out-of-support Microsoft Exchange Server 2010. The patches for these vulnerabilities should be applied as soon as possible. Microsoft Exchange Online is not affected.
Patches for an additional three vulnerabilities in the same software have also been released: CVE-2021-26412 , CVE-2021-26854 and CVE-2021-27078 . It is believed that these vulnerabilities have not yet b
Sentinelone
SentinelOne and HAFNIUM / Microsoft Exchange 0-days
blogs_sentinelone·2021-03-04
SentinelOne and HAFNIUM / Microsoft Exchange 0-days
On Tuesday, March 2nd, Microsoft released an out-of-band security update addressing a total of 7 CVEs, four of which are associated with ongoing, targeted attacks. The update was in response to an active campaign that was seen on Microsoft clients compromising Exchange servers by bypassing authentication and allowing attackers to read emails and potentially penetrate enterprise networks without the need to authenticate.
The SentinelLabs team has been closely tracking HAFNIUM and Exchange Server impacts. Customers with the Deep Visibility threat hunting module (STAR) may also automate responses (alerts, network quarantine, kill, quarantine) should these IoCs be seen in the future. Our customers can stay ahead of this emerging threat with our protection capabilities and real-time alerts.
#
Qualys
Microsoft Exchange Server Zero-Days (ProxyLogon) – Automatically Discover, Prioritize and Remediate Using Qualys VMDR
blogs_qualys·2021-03-03·CVSS 9.1
[CRITICAL] Microsoft Exchange Server Zero-Days (ProxyLogon) – Automatically Discover, Prioritize and Remediate Using Qualys VMDR
## Table of Contents
CVE Technical Details
Attack Chain
Discover and Remediate the Zero-Day Vulnerabilities Using Qualys VMDR
Post-Compromise Detection Details
References
Update March 10, 2021 : A new section describes how to respond with mitigation controls if patches cannot be applied, as recommended by Microsoft. This section details the Qualys Policy Compliance control ids for each vulnerability.
Update March 8, 2021 : Qualys has released an additional QID: 50108 which remotely detects instances of Exchange Server vulnerable to ProxyLogon vulnerability CVE-2021-26855 without authentication. QID 50108 is available in VULNSIGS-2.5.125-3 version and above, and is available across all platforms as of March 8th, 1:38 AM ET. This QID is not applicable to agents, so the signature versi
Qualys
Microsoft Exchange Server Zero-Days (ProxyLogon) – Automatically Discover, Prioritize and Remediate Using Qualys VMDR | Qualys
blogs_qualys·2021-03-03·CVSS 9.1
[CRITICAL] Microsoft Exchange Server Zero-Days (ProxyLogon) – Automatically Discover, Prioritize and Remediate Using Qualys VMDR | Qualys
#### Table of Contents
- CVE Technical Details
- Attack Chain
- Discover and Remediate the Zero-Day Vulnerabilities Using Qualys VMDR
- Post-Compromise Detection Details
- References
Update March 10, 2021: A new section describes how to respond with mitigation controls if patches cannot be applied, as recommended by Microsoft. This section details the Qualys Policy Compliance control ids for each vulnerability.
Update March 8, 2021: Qualys has released an additional QID: 50108 which remotely detects instances of Exchange Server vulnerable to ProxyLogon vulnerability CVE-2021-26855 without authentication. QID 50108 is available in VULNSIGS-2.5.125-3 version and above, and is available across all platforms as of March 8th, 1:38 AM ET. This QID is not applicable to agents, so the signature
Tenable
CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065: Four Zero-Day Vulnerabilities in Microsoft Exchange Server Exploited in the Wild
blogs_tenable·2021-03-02·CVSS 9.1
[CRITICAL] CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065: Four Zero-Day Vulnerabilities in Microsoft Exchange Server Exploited in the Wild
## Cloud Exposure
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## Vulnerability Exposure
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## Identity Exposure
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## Business needs
Active Directory
AI Security Posture Management (AI-SPM)
AWS security
Azure security
Cloud Security Posture Man
Crowdstrike
March 2021 Patch Tuesday: Updates and Analysis
blogs_crowdstrike·CVSS 7.5
CVE-2026-20929 [HIGH] March 2021 Patch Tuesday: Updates and Analysis
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How Charlotte AI AgentWorks Fuels Security's Agentic Ecosystem Mar 25, 2026
Video Highlights the 4 Key Steps to Successful Incident Response Dec 02, 2019
Helping Non-Security Stakeholders Understand ATT&CK in 10 Minutes or Less [VI
2021-03-03
Published