Vulnerability Details : CVE-2021-26858
Used for ransomware!
Microsoft Exchange Server Remote Code Execution Vulnerability
Vulnerability category: Execute code
Products affected by CVE-2021-26858
- cpe:2.3:a:microsoft:exchange_server:2010:sp3:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2013:sp1:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_8:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_9:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_10:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_11:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:-:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_22:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_12:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_1:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_13:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_2:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_14:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_3:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_18:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_7:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_15:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_16:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_17:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_4:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_5:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_6:*:*:*:*:*:*
CVE-2021-26858 is in the CISA Known Exploited Vulnerabilities Catalog
This issue is known to have been leveraged as part of a ransomware campaign.
CISA vulnerability name:
Microsoft Exchange Server Remote Code Execution Vulnerability
CISA required action:
Apply updates per vendor instructions.
CISA description:
Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution. This vulnerability is part of the ProxyLogon exploit chain.
Notes:
Reference CISA's ED 21-02 (https://www.cisa.gov/news-events/directives/ed-21-02-mitigate-microsoft-exchange-premises-product-vulnerabilities) for further guidance and requirements. Note: The due date for addressing this vulnerability aligns with the requirements outlined in ED 21-02. https://nvd.nis
Added on
2021-11-03
Action due date
2021-04-16
Exploit prediction scoring system (EPSS) score for CVE-2021-26858
17.45%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 96 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-26858
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
6.8
|
MEDIUM | AV:N/AC:M/Au:N/C:P/I:P/A:P |
8.6
|
6.4
|
NIST | |
|
7.8
|
HIGH | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
1.8
|
5.9
|
NIST | |
|
7.8
|
HIGH | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
1.8
|
5.9
|
Microsoft Corporation |
References for CVE-2021-26858
-
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26858
CVE-2021-26858 - Security Update Guide - Microsoft - Microsoft Exchange Server Remote Code Execution VulnerabilityPatch;Vendor Advisory
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