How severe is CVE-2021-31196?

CVE-2021-31196 has a CVSS 3.1 base score of 7.2 (HIGH). EPSS estimates a 54.1% probability of exploitation in the next 30 days. It is listed in the CISA Known Exploited Vulnerabilities catalog.

CVE-2021-31196: Microsoft Exchange Server Remote Code Execution

CISA Known Exploited Vulnerabilities

Microsoft Exchange Server Information Disclosure Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV

2024-08-21

Remediation due

2024-09-11

Required action
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

CISA notes
https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2021-31196; https://nvd.nist.gov/vuln/detail/CVE-2021-31196

Description

Microsoft Exchange Server Remote Code Execution Vulnerability

Severity

CVSS 3.1 · CNA7.2 HIGH

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

SSVC · CISA-ADP

Exploitationactive

Automatableyes

Technical impacttotal

Exploitation Context

as of October 17, 2026

All KEV statistics→

CISA added CVE-2021-31196 to the KEV catalog 1,134 days after its CVE record was published. The median for entries added in 2024 is 21.5 days.
It is one of 391 Microsoft entries in the CISA KEV catalog, and one of 36 added in 2024.
Its current EPSS score (54.1%) is higher than that of 51% of CISA KEV entries.

Affected Products

Vendor	Product	Affected versions
Microsoft	Microsoft Microsoft Exchange Server 2013 Cumulative Update 23	15.00.0 to <15.00.1497.023
Microsoft	Microsoft Microsoft Exchange Server 2016 Cumulative Update 20	15.01.0 to <15.01.2242.012
Microsoft	Microsoft Microsoft Exchange Server 2016 Cumulative Update 21	15.01.0 to <15.01.2308.014
Microsoft	Microsoft Microsoft Exchange Server 2019 Cumulative Update 10	15.02.0 to <15.02.0922.013
Microsoft	Microsoft Microsoft Exchange Server 2019 Cumulative Update 9	15.02.0 to <15.02.0858.015

References

2 Links

Vendor advisories

Microsoft Exchange Server Remote Code Execution Vulnerability

Other references

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31196

Record Details

Published

2021-07-14

Last updated

2026-08-10

Assigner (CNA)

microsoft

Credited to

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CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.