CVE-2021-31196
HighExploitedPublic exploitMicrosoft Exchange Server Remote Code Execution Vulnerability
Published Jul 14, 2021 · Updated Aug 10, 2026
Key Facts
Patch immediately- CVE-2021-31196 is a high-severity vulnerability (CVSS 7.2 v3.1) affecting Exchange Server (Microsoft).
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 14, 2022. Public exploit code is available.
- EPSS estimates a 54% probability of exploitation in the next 30 days.
- Fixed versions are available, including Exchange Server 15.00.1497.023, Exchange Server 15.01.2242.012, Exchange Server 15.01.2308.014.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
7.2
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
54%
Higher than 98.9% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-31196 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
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Aug 21, 2024 | Sep 11, 2024 | Not reported |
| Industry KEV feed | Sep 14, 2022 | Sep 11, 2024 | Not reported |
| CIRCL KEV | Aug 21, 2024 | Sep 11, 2024 | Not reported |
| ENISA EUVD | Aug 21, 2024 | n/a | Not reported |
Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Affected Products
5 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Exchange ServerMicrosoft | 2013-cumulative_update_23, 2016-cumulative_update_20, 2016-cumulative_update_21, 2019-cumulative_update_10, 2019-cumulative_update_9 | 15.00.1497.023 |
Patched Releases
Exchange Server
15.00.1497.023, 15.01.2242.012, 15.01.2308.014, 15.02.0858.015, 15.02.0922.013
Timeline
Publicly disclosed
Jul 14, 2021
Added to Industry KEV feed
Sep 14, 2022
Added to CISA KEV
Aug 21, 2024
Added to CIRCL KEV
Aug 21, 2024
Added to ENISA EUVD
Aug 21, 2024
Last updated
Aug 10, 2026
References
- patchhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31196
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- otherhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-31196
FAQ
Common Questions.
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected: Exchange Server (Microsoft) versions 2013-cumulative_update_23, 2016-cumulative_update_20, 2016-cumulative_update_21, 2019-cumulative_update_10, 2019-cumulative_update_9. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 14, 2022.
Yes. It was added on Aug 21, 2024 with a federal remediation due date of Sep 11, 2024.
Public exploit code is available.
Fixed versions are available, including Exchange Server 15.00.1497.023, Exchange Server 15.01.2242.012, Exchange Server 15.01.2308.014.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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