Which products and versions are affected by CVE-2021-31195?

Affected: Exchange Server (Microsoft) versions 2013-cumulative_update_23, 2016-cumulative_update_19, 2016-cumulative_update_20, 2019-cumulative_update_8, 2019-cumulative_update_9. The full list is in the CVE brief.

Is CVE-2021-31195 being exploited in the wild?

It is not listed in any known-exploited vulnerabilities catalog.

Is CVE-2021-31195 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Is there a public exploit for CVE-2021-31195?

No public exploit code is known.

Is there a fix for CVE-2021-31195?

Fixed versions are available, including Exchange Server 15.00.1497.018, Exchange Server 15.01.2176.014, Exchange Server 15.01.2242.010.

How urgently should CVE-2021-31195 be patched?

Brandefense priority: patch immediately, because it is very likely to be exploited soon.

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Vulnerability Intelligence

CVE-2021-31195

High

Microsoft Exchange Server Remote Code Execution Vulnerability

Published May 11, 2021 · Updated Feb 28, 2025

Key Facts

Patch immediately

CVE-2021-31195 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Exchange Server (Microsoft).
It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
EPSS estimates a 74% probability of exploitation in the next 30 days.
Fixed versions are available, including Exchange Server 15.00.1497.018, Exchange Server 15.01.2176.014, Exchange Server 15.01.2242.010.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

CVSS v3.1

8.8

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS (30-day exploit likelihood)

74%

Higher than 99.4% of all scored CVEs

Exploited in the wild

No known

Not in a known-exploited catalog

Public exploit code

None known

Get the full CVE-2021-31195 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

Microsoft Exchange Server Remote Code Execution Vulnerability

Affected Products

5 affected entries in total

Product	Affected versions	Fixed in
Exchange ServerMicrosoft	2013-cumulative_update_23, 2016-cumulative_update_19, 2016-cumulative_update_20, 2019-cumulative_update_8, 2019-cumulative_update_9	15.00.1497.018

Patched Releases

Exchange Server

15.00.1497.018, 15.01.2176.014, 15.01.2242.010, 15.02.0792.015, 15.02.0858.012

Timeline

Publicly disclosed
May 11, 2021
Last updated
Feb 28, 2025

Weakness Type

CWE-290 Authentication Bypass by Spoofing

References

patchhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31195

FAQ

Common Questions.

Microsoft Exchange Server Remote Code Execution Vulnerability
Affected: Exchange Server (Microsoft) versions 2013-cumulative_update_23, 2016-cumulative_update_19, 2016-cumulative_update_20, 2019-cumulative_update_8, 2019-cumulative_update_9. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Exchange Server 15.00.1497.018, Exchange Server 15.01.2176.014, Exchange Server 15.01.2242.010.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

Is CVE-2021-31195 Running On Your Attack Surface?

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