SARA / Free Tools / CVE / CVE-2021-27065

CVE-2021-27065 — Microsoft Exchange Server Remote Code Execution Vulnerability

Microsoft Exchange Server Remote Code Execution Vulnerability

CVSS
7.8 HIGH
EPSS
94.28% (top 0.10%)
CWE
Published
2021-03-02T23:55:28.000Z
Last modified
2025-10-21T23:25:52.706Z
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
CISA KEV — Actively Exploited
Added to KEV
2021-11-03
BOD 22-01 due
2022-05-03
Ransomware use
Known

01What is this vulnerability?

Microsoft Exchange Server Remote Code Execution Vulnerability

02Affected products

VendorProductVersions
MicrosoftMicrosoft Exchange Server 201915.02.0
MicrosoftMicrosoft Exchange Server 2013 Cumulative Update 2215.00.0
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 215.02.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1315.01.0
MicrosoftMicrosoft Exchange Server 2013 Cumulative Update 2315.00.0
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 315.02.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1415.01.0
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 415.02.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1515.01.0
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 515.02.0
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 615.02.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1615.01.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1715.01.0
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 715.02.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1815.01.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1915.01.0
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 815.02.0
MicrosoftMicrosoft Exchange Server 2013 Service Pack 115.00.0
MicrosoftMicrosoft Exchange Server 2013 Cumulative Update 2115.00.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1215.01.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 815.01.0
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 115.02.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 915.01.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1015.01.0
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1115.01.0

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2021-11-03. Ransomware use: Known.

04Recommended remediation

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

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07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

09References

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