Vulnerability Details : CVE-2021-26858
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.
Vulnerability category: Execute code
CVE-2021-26858
is in the CISA Known Exploited Vulnerabilities Catalog
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/emergency-directive-21-02) for further guidance and requirements.
Added on
2021-11-03
Action due date
2021-04-16
Exploit prediction scoring system (EPSS) score for CVE-2021-26858
Probability of exploitation activity in the next 30 days: 36.77%
Percentile, the proportion of vulnerabilities that are scored at or less: ~ 97 % EPSS Score History EPSS FAQ
CVSS scores for CVE-2021-26858
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|
|
6.8
|
MEDIUM | AV:N/AC:M/Au:N/C:P/I:P/A:P |
8.6
|
6.4
|
[email protected] |
|
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
|
[email protected] |
References for CVE-2021-26858
-
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26858
Patch;Vendor Advisory
Products affected by CVE-2021-26858
- cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*
- 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:*:*:*:*:*:*